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Taser Univ Wisc Eval and Analysis 1976

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DEPARTMENT OF ELECTRICAL
AND CorJlPUTER ENG'NEERING

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5401 Westband Avenue, Room 918
Bethesda, Maryland 20207

Dear Mr. Zylich:

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February 12, 1976

Mr. Heil P. Zylich
Hazard Analysis Engineer, SES
COnsumer Product Safety Commission

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1425 Johnson Drive
Madison, Wisconsin 53706
Telephoftl: 6081262-3940

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I have completed my analysis of the information you sent me wi t.fl
your letter of Februar . 4 concernin the Taser Public Defender elecf:-ll·
~__~u_n_.__ T e pr~mary emp aS1S 1n my stu y was to
eterm1ne w et er t e
Taser electrical out' ut can be lethal. I did not ea W1t ot er po:-

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at wou -pro a y e non-lethal such as electrical
burns or physical injury caused by the darts.
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of-the load

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The electrical output for a device is· a function
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that device. The Taser output was tested with resistance loads of
00, sao an~ :LOOO ohms as wEll as higher resistance loads. I per:or;- -.-:-;
none of these tests but have evaluated the test results. With tne
Taser darts fUlly inserted into tissue, the exposed d.rt area per ca::
would be about 5.5 mm 2 • Geddes and Baker show impedances between pa~·-:
of needle electrodes to be approximately 1000 ohms for 5.6 mm 2 ex?os:area electrodes and approximately 300 ohms for 73 mm 2 electrodes.
[L.A. Geddes and L.E. Baker, Prine! les of A lied Bicmedical Instrumentation. New York: John W~ley, 1975, pg_ 248.
Since the Taser
iIectrodes have barbs and are forcefully inserted, it would se~~ that
local trauma would increase the effective area of the barb and thus ce~
crease electrode resistance to the 200 to 1000 ohm range •.

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Tests were conducted to determine the Taser output into 200, 50~
and 1000 ohm resistive loads. The outDUt consisted of a train of, c~~=e(
a nUS01 5 w~t a requency or t e pu ses 0
Hz. One pOSS1 e rnea~s
for evaluating the safety for the Taser output is to compare the output to the output of a device that provides shoeks that are conside:'-.
safe for humans. A endix F su lies a sum.9fla: for the maximum outP~. . "----or an e ectr1c enee con ro or 1nto &
C
0& as spec~.~e
Y
Underwriters Laboratories. It i . seen tha~ pulses with an enerqy ~f.
approximately 90 mJ per pulse 1s maximum. The maximum pulse repetlt~on
~ate 1. about 1 Hz - off period must be greater than 0.75 seconds.
.n
Appendix A, the energy per pulse for the Taser was calculated for 200,
500 and 1000 ohm loads. The results were:

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500

1000

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13.6'
102.2
140

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the ~aser output energy per pulse is somewhat higher than the
allowable output. for 4ft .loetric fence. A mere impcrtant point, howev.~
1. that the Taser pulses occur 13 times per second compared to the once
· per second for the fanee. The powor into the load is then 13 times
greater for the" Taser output than .for the electric fence. These result
indicate that the Taser output is more hazardous than an electric fence
output.
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'~hus,

••cause the Taser output consists of a pulse train, it appears

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compare this output to the known effects of steady state sinu80ida1 currents. Much work has been done on the effects of different
values of effective, rms, currents and on the effect of different frequencies. In Appendix S, the effective value for the Taser output
current is calculated. The results are:

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Rx,(Q)
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Irma (mA)

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200

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sao
1000

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60

11.6
42.7

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For 60 Hz, alternating curr'&nt, the current that will cause ventricu·:~:·
fibrillation in one out of two hundred individuals is greater than
approximately
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"150

rnA

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where 'j' is in seconds. This expression is valid for ·S. 3 ms < T < Ss
with the value of current from 5 ~o 20 seconds about the same as for
5 •• conds. '1'he con&t.ant,. 1-6.o-is~ometi.me5 reduced to 100 when consic.-·
Ing safe current levels for children. 'rhe effective current output ::'".
the Taser appears to be close to the "level that can 'cause ventricula~
fibrillation and death except for the fact t.hat the heart does not r'.
pond readily to hi;her frequency currents. The lethal level for 60 ~
cu~rent cannot be co~pared dir~ctly to the total effective current
output of the Taser because the Taser output has high frequency compL""
ents that have negligible effect on the heart •
.

. To include the response of the heart to the frequency of the
electric current, the frequency spectr~~ for the Taser output was Cc

eulated in Appendix C. Appendix D provides a calculation for the
effective value for each of the frequency components for the Taser 0".. ,;.
put; in addition, compensation is included in the calculations to
include the fact that higher frequency components have less effect C·
the heart. It is shown in Appendix D that a conservative approach, .. ~
that: maximizes any danger, is ~o .s.ume tha~ the heart. responds equz.:. .-~Y
to all frequencies of current to 13 kHz and does not respond to frequencies above t.his value. Taking equal magnitudes for all frequenc''''
components below 13 kHz 1n the Taser output and with a 13 kHz cut-of:,
~. following effective· currents wer, calculated:
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Irma
(mA) .
Rx,
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100

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500

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8.7

10.'

1000-

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it appears thAt the maximum Taser output current is approximatoly
10' of the lethal value. The current is about twice the 5 rnA let-go
. cur~ent level which seem, to explain why the shocks are effective in
incapacitating an individual.
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Appendix E includes a discussion of the '1'aser provided test resul ':5

and

~.ferences.

Conclusions

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.,... 'laser electrical output i . not lethal •.

shocking device, there may be cases of
lethality because of individual susceptibility.

2.

Ja with any electric

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hazard in the output would be increased if the pulse repetition rate
should
increase
or
the
amplitude
of
the
output
increased~
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Sincerely,

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Dr.
Professor

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Bernstein
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•Theodore

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FEB II

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LNTEO STATES CiOVEFlNMENT

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Memorandum.
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SAFE TV COMMISSION

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WASHINGTON, O~ C~ 2020~

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>:0'" ~\'I~_. CONSUMER I=~OOUCT
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.Albert F. Each, M.D., Director, OMD

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10, 1976

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'Leo T. Duffy, M.D., Deputy Director
Office of the Medical Director

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'rASER TF-l, CP-1

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of the "Medical "Director has reviewed the
ma.terial submitted by your Offi'ce concerning the subject petition. Although this reply will concern itself
only with -the meaical aspects of this subject, we
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recognize at the' starOt -t.hat this product is manufactured as a -dangerous_weapon-, and should be so treated.
As such, its effectiveness '~epends on the creation
of some measure ~f injury in order to fulfill.its.
intended purpos~. Therefore, it appears that the role
of this Office is more concerned with assessing the
• r 1sk of un.re,!sonable inj ur~" rather thlln th~ .. un·r easor.able
~he.Office

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This memorandum will' not 'address
tFie soc ia 1-;' moral -ana ·pnilosophical issues which are

necessarily bound to be raised in the diseussion
· consideration of the use of this product.

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From the electrical data supplied as the design output,
and our survey of the literature (references -attached),

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it 1s apparent that the stated available electrical
current (50,000 V/O.3 joules/10 pps) is'non-lethal
when the wea on is used as directed on the "avera e,

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y aut.

e current-re ate

lnJury sustalne

with the intended use of the TASER is relate~ to the
neuromuseular system, and 1s exhibited as an abnormal,
tetanic or sustained contraction of musele groups which
has the effect of immobilizing the recipient,.

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This

reaction is induced by the action of the electric .
current passing through the skin, and then following ·
nerve pathways by means of the nerve fibrils (cells)
'and their myelin sheaths, both of which.are excellent
~~nduetors. .The current is then continued through
n.r.ve en~ings (synapses) which are attached to muscle.
• ~he transference of the charge to the muscle cell.
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s them to contract. This_ in ur process, ordinarily,
..a temporary and reverslb e w en use as n ca e
on the health human. ~he level of current is com arable
to t at 0 U.L. approve e ectr c w re e~ce• •s at
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as the afreezing- action is concerned.

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However, a
aajor ~ifference exists in that the electric fence
pulsed charge of approximately 4.0 mAmp has OFF ana
ON periods which would allow the ability to -letgo·,
and get free from the fence. With the TASER the Wlet10· is dependent on the user interrupting the flow
of current by releasing the release bar.

exposure to the state~ amount of TASER current,
there 15 a wi~e margin of safety as related to causing
severe car~io~Yascular reactions. An alternatin
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current 0
mperes,
0 t,
z can resu t
in ventricular fibrIllation. This is an asynchronous,
uncoordinated rhythm of the heart beat which is incompatible with survival unless the normal rhythm is
restorea b means of a defibrillator ~eviee. The TASER
current 0
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JOu es watts seCQn ) 15 we
e ow
the 10 to 50 joule threshold above which ventricular
fibrillation can occur~ This saf t m
in woula e
lmlnlS e 1n a person ~ 0 as ex stln9· car io~vascular
disease. For example, an elderly person with arteriosclerotic
heart disease would be subject to the precipitation
of heart failure under the stress of convulsive seizures
associated with Electric Shock Therap~. The margin
of safety woulc! also be reduced with a prolong't9__continuation
of TASER cur rent.
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Injuries related to the impact of the barbed darts
causing puncture wounds of the external surface of the
body would be relatively minor, except for impact on
the eye. ~he chance for initiation of events leading
to a total loss of vision in the affected eye would
be extremely high should such contact occur. Electric
energy applied in the vicinity of the ey~ has also
resulted in delayed cataract formation.
There is no evidence that adverse psychological, or
neurological, effects, stemming purely from the electric
current charge of a TASER, would be induced.
Injuries, resultin9 from falls involving an incapacitated,
inert hum~~ body, are speculative dependin9 upon the
activity O~ the recipient at the time of impact, and
on contact with external hazards, such as the head
.trlking the sharp corner of • table. The likelihoo~
of injuries, such as fractures, is increased 1n the
e.se of the aged or physically handicapped.

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In general, the severity of systemic effects from the
passage of electric current thr~u9h the body depends
on aeveral factors. These are: 1) type of circuit,

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2) voltage, 3) value of the current, .) duration of
flow, 5) resistance of specific tissue, 6) area of
contoct, and 7) pathw3Ys followed through the body •
In a~dition, people with chronic cardio-vascular 4isease,
the elderly and children woula be incr•• sin 1 ausce tible
o a verse e ec s.
ere ore,
15
lee ai ree_s _
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with the conclusions stated by the manufacturer In
. his summary of May 10, 1972, page 3, which reads
----the conclusions reached as a result of these studies
and special tests is that the TASER is non-lethal at
the design output to normally healthy people. However,
it must b~ .rnphasized that neither this feature nor
the non-injury or no harmful after-effect aspects can
ever be guaranteed. There is no weapon, technique
or procedure for subduing, constraining or aispersing
that does not involve some risk of injury to healthy
persons or of death especially if the individual has
a heart ailment."

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LNlTEC STATES GOVERNMENT

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Memorandum

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WASHINGTON. O. C. 20207

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TASER Evaluation and Analysis

S&..IILJIICT~

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DATII~

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: Neil P. Zy11ch, Hazard Analysis Eng1nee;\1f
Special En&1neer1ng Studies Division

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Technical Analysis Division

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CONSUME~ P~ODUC

SAFETY C:OMMtSSJO:.j

Joseph Z. Pandey

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U.S.

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Engineering Sciences was requested by the
Orfice or·Standards Coordination and Appraisal to evaluate
the TASER Public Defender tor potential for inJury.

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The !ureau

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DESCRIPTION,

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The TASER is a battery operated device t.he size of a large
flashlight (dimensions" are gU x 3u xZ" and l-leighs 1-1/4

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pounds). It contains a cartridge-like insert that when
actuated by a s~all charge or ~ow~erJ pr~pels two small
darts. Each dart is connected by a'wire 18 teet in length
to a- t"ransfcrrrner power' source \111 thin the TASt:R. When
the darts are propelled, if they strike either skin or
clothing they will imbed t'he:r.selves in it. If both darts
1mbed the~selves in either skin or clothing on a person,
the person can be subjected to an electrical shock.
Note. the darts do not have ·to make physical contact
with a person but just attach themselves to a person's
clothing in order for the person to receive an electrical
shock. The holder or the TASER depresses a switch on
the TASER after the darts have been f1red and imbedded
in order to transmit an electrical shock to the intended
victim. The electrical shock lasts as long as the switch
11 depresse~. Approx1~ately two to three ~inutes is the
maximum time duration the electrical shock c,n be applied
continuously before the battery is discharged and the
TASER become3 1nerrect~ve.

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S~bJect:

~ASER

Evaluation and Analysis

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BACKGROUND
SEZ throur:~ CSC~ obtained t\le '.:'A~E~S, a circuit descr1p-

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tlon of the TASER, and test and operational literature
on the TASEn. After an initial rev1ew and analysis of
the TASER by BES (which included taking photoeraphs
. of the TAS[~output waverorm at various impedances
which simulated body impedance; see Attachment 3) it was
decided to concentrate on the electrical aspect~ of the
TASER only. The injury effect of the pointed darts was
considered. It 15 concluded that the barbs will penetrate
human skin to arnaxirnum depth of approximately 5/16".
The most obvious ser10uG injury 'Ilh1ch could result from
the dart itself would be an injury to the eye.

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BES contractea with Dr. Theodore Bernstein or the ·
University of W1scons1n~ ~co!nlzed'aufnor1tl-1nthe
tte~d. of electric. shock effects, to evaluateSLana anaIYze
the TASER eleetrical. output. The TASER output wavero~rns
t/ere measured at the IJat10nal Bureau or Standarcs by
CPSC personnel a~d photographed. This information, a
TASER. and literature made available by the TASER manu~
facturer concernin6 ~he testing end safety or the ~evice
were supplied to Dr. Bernstein for evaluation.
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BES has reviewed Dr. Eernste1n's analysis, a copy or
which is attached. Attachment 2 contains specitic
comments and/or clarification concerning th1s analysis.
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RESULTS
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The calculated effective current to which an individual
would 'be subjected 1s approximately ten milliamperes.
This current is above the threshold or the "let go"
current value in the 11t~rature ror Which test data is
available. Professor Dal!1e~reported on tests conducted
.on volunteer subjects: bO~ of the women tested and 15~
or the men tested could not let go or a current 1n excess
or la ma. While th10 value caused pain, no permanent
injury resulted. These tests were conducted at 60 hz. '
It should be noted however that.~he erfect or let go
1. a t~nct1on or frequency as Wt':":':' as current • At
trequenc1es above 100 hz the efrects or current decrease
such that the let go current increases. For example
the f1fty percentile let 10 threshold tor men at 60 hz
is 17 ma While the fifty percentile let go threshold
tor men at 10 khz is 7~ rna. Thus the 10 khz threshold
"1s over tour times as high as tor 60 hz •
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Irrotessor Charles Dalziel or the ~n1vers1ty or Callfornja,
reco~niz~d lendjn~ authority in thIs field prIor to hi:
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Subject:

TASER Evaluation and Analysis

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Dr. Bernstein states that the "maximum TASER output 1s
rox1matel 10~ or the lethal value". 'this rel:i.tes

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e va ue 0 rrns curren
or a
requency c mponen s
up to 13 khz of approximately 10 ma to the commonly
accepted value or 100 ma tor ventricular fibrillation
or a normal adult human. Proressor Kouwenhoven in his
paper on "Effect of Electric Shock" 1n the Transaction
or A.I.E.E. V.~9, January 1930, p. 381 stated that
100 milliamperes may cause death and that for norwal
pers~ns the current should not exceed 30 milliamperes.
Ferris, Spence, Williams and King stated
in
the~r report,
tl
"Efrect of Electric Shock on the Heart 1n Electrical
Engineerins, v. 55, May 1936, p. ~98 that the maxl~u~
current to which man may safely be subjected for shocks
or one second or more in duration is about 100
Jn1111amperes. Dalziel and Le'e have shown wi th tests
•
on dogs in their report "Lethal Electric Currents"
in the February 1969 IEEE Spectrum on Page ~8 that the
average 100 pound or more animal require's approximately
100 milliamperes for ventricular fibrillation.
H. Spencer Turner in his report on "Human Responses to
Electricity A Literature Review", Ohio State University
Research Foundation) 1972 on Page 43 states that sinu·~-~so1aal·currents in excess of 100 ma at 60 hz from ha~d
to root will be dangerous for shock durations of three
seconds or more for man.

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With regard to establishing a standard tor such a device;
simply 5tated, a standard would address such devices
tor both AC and DC operation.

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The energy output of such devices would ·have to be der~ned
in terms or frequency, pulse heisht, pulse width, on
and ofr time of pulses. The maximum energy would then
have to be determined tor various frequency bands such
that at least the 30 dispersion or the population would be
covered. The definition or the energy levels would
depend on medical Judgements, and whatever data may be
available in the literature.
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SubJect:

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TASER Evaluation and Analysis

COI~CLUSIO:J

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. In conclusion, BES !Srees with the finding that the TASER
should not be lethar-to a norm 1 hea thy erson. ~'h1s is
~asec on a comparison of Dr. Bernstein's engineering
results with the' known engineering data in the literature.
Additionally a standard could be develope~ but not
without a costly and time consuming program to do so.
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EVALUATION OF THE ELECTRIC SHOCK
HAZARD FOR THE NOVA XR 5000
STUN CUN

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Theodore Bernstein. Ph. D•
Prof.ssor of Electrical and Computer
Engineering

1
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II

University of Wisconsin-Mldlson

.

January 22. 1985

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ABSTRACT

The elKtric shock hazlrd for the XR 5000 is determined by com~ring
the shock delivered to the known .ffects of I 60 Hz shock. With &0 Hz .
shocks I current of 1 mAil It the threshold of perception. 5 IlIA II It the
let-go current 'eve' where shocks Ire painful but not dangeroul. and SO mA
II the level where ventricular fibrillation Ind duth can occur. The XR 5000
.. output il • trlln of damped. sinusoidll pulse. with an approximate 10 liS
time conltlnt. The true r.m.l. valulof the output II not 1 wild Indication
of the hazlrd because the output conginl frequency components well above
the 1 kHz frequency above which the .tfKt for I given f.-.qu.ncy component
II reduced. When th... '-ctors .r. conlldered, the output for the XR 5000
. II In the 3 to • mA ring. of .n Iqulvllent 10 Hz shock and il not dang..ous~ The fact that the Ihock II dellverld betw..n two probe. 2 inches
lpart adds to the .afety becaus. the currlnt Is concentr.ted In the region of
the body betw~n the two probes Ind only'. negligible current an reach the

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'NTRODUCTION

The design of molt electrical equipment, ensures that an IndividuAl
should r.r.'y contact energized parts and be subjected to .Iectrlc shock.
For such equipment electrica' safety
provided primarily by Inlulatlon or
·gUlrdlng to prevent contKt and by lultable grounding. Any cont.ct with
energized plrts Is considered hazardous. There are other equipment where,
even though it Ny not be Intended, contlct with energized p8rtl' il
expected 10 that the electrical safety must be provided by ensuring that any
..
posslbl. .Iectric shock will not be MZlrdous or lethal. Example. of such
electricil devices Ire the. electric fenCl, medicI I electriclJ nerve Itimuilitors,
.elder, cattl. prod, Ind fly .Iectrocuter. The Nova XR SOOO stun. gun il In
exampl. of I new device where individuals Ire deliberately subjected to

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Ilectricll shock.
The XR 5000 is • small, hand-held device powered by • tV bIIttery.
.

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Ther. ar. two small pr-obes extending from the front approximately 5
lllllIlmeters, 2 Inche. IPirt. The probe. are intended to be pressed into an
attKker'l body 10 thlt an .Iectrical shock can be delivered to Incapacitate
•
the atucker. It's Important that the IttKker not be injured, a. this Is one
of the major advlntages of the device.
This repOrt evalultes the safety of the shock delivered by the XR 5000.
This is done by analyzing the output current wlveform Ind compa,.ing thl,
shock to known safe Ind hazardous shocks. Safety criteria .for the electric
fence ar. used to compar. the Ihock delivered to thlt delivered by the XR
SOOO.
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SINUSOIDAL, 10 Hz SHOCKS
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ElectrIcal shocks Involving Iiternating current hive been Inve.tlglted
since before 1110 (Bernlt_ln. 1975 ) • htost of the recent Itudl. hive
Involved sinusoidal, 50 or 10 Hz currents, thoug h the effects of other
•
frequencle. and waveforms have also been stUdied. This report compares
the shock delivered by the XR 5000 to an equivalent 60 Hz shock. In order
to do this, the ,ffects of 10 Hz shocks Ire reviewed.
Thr.hold Of '.rcept!on
For 60 Hz shocks, the lowest level of curr.nt that can be • problem is
the threshold of perceptIon level. This leve., where some people may feel I
slight tlngl.· but should have no extreme Itartle reaction, I. usually conIldered to be 0.5 mA r.nt."I. for 10 Hz. currents Ind II the IIIIxlmum _llowl~
.
bl. I.ak.ge current for appliances (ANSI, 1973). Dalziel and MIlnsfield
(1950) have determined that the median threshold of perception current at
10 Hz WIS 1.017 InA for 21, men Ind 1. 11 mA for four women. Shocks "elr
but abov. the thr.shold of perception current may be I hazlrd beaus. of
Injury aused by the Itlrtl. ruction producing a dangeroul body motion.
Ventricular Flbrlilition
At the other extreme il the level of current where the hMrt mlY be
thrown Into ventricular flbrill_tion Ind dMth occurs. For shocks between
any two limbs, Biege'mei.r and L.. (1 '10) have re-evlluated experimental
Uti on ventrlcullf flbrlilition Induced by electrical shock in InlNls Ind
related the results to the physiological response to electrical shocks. For
short du tlon shocks shorter thin I clrdlac cycle. the electrical tcurrent to .
c.use flbrlliition must b.
and occur during the vulner.ble period, T
wave. Shocks longer than a cardl.: cycle can CIUle pr..-tur. ventricullr
contrlCtlonl that lower the shock threshold current to I minimum Ifter four
,

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or flye pretnltur. ventrlcullr contractions.' Using these concepts, a ~fe
current limit hal been established •• sao inA for shocks .... thin 0.2
ReO. .
In duration and SO mA for shocks lange, than 2 HCondl. For
shocks between 0.2 and 2 seconds, the .If. current ,. Ilyen by the expres-

lion

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1 • 100/T mA

(1 )

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wheN T il In HConds and 0.2 l e T c 2 I.
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Let-Co Current
The let-go current level of shock is not immediately lethal as Is the
ventricular fibrillation level. "'t this level of shock. with a current path
through the arm. the Individual cannot let go of an ener~lzed conductor.
This
level
II
hazardoul
In
that
a
person
Is
receiving
a
very
pelnful
Ihock
•
from electrlca' equipment that he cannot relllie. Such a long duration
lhock may eventually become hazardous because of evoked heart arrhythmias
or a decre..e In contact rellstance because of perlplratlon or burns allows
,
grllter currents. Dalziel and Malloglla (1956) have determined that the
60 Hz I,t-go current level where 0.5\ of the Individuals cannot let-go Is
9 mA fOr men and 6 m'" for women. The median let-go leve' Is 16 m'" for
men and 10.5 m'" for women. " The let-go level where 99.5\ of the Individuals
cannot let-go Is 23 m'" for men and 15 mA for women. Underwriters
Laboratories (1972) requires that the ground fault circuit interrupter trip
with long duration shocks greater than 6 mA as most people can let-go at
currents less than 6 m.... The electric fence controller (Underwriters
Laboratories 1980) II designed so that any lingle controller failure will not
produce a continuous current greater than 5 m'" because of the let-go
problem. Currents above an individual's let-go current level could be
hazardous and painful because the Individual would be frozen to the circuit.
EFFECT OF FREQUENCY

,
The frequency of the electrica' current Is Important In determining the
effect on the human body of a given magnitude of current. When testing
appliances or medical devices for leakage current. test loads have been
devised which are supposed to simulate the response of the human body to
the varioul frequency components In the leakage current. In order to do
thll. an electronic voltmeter II connected acrOSS the simulated load in such a
fashion that a glv~n reeding of the voltmeter at any frequency II equivalent
to the same effee..•hock. Underwrite,.. Laboratories (1976) lpeclfles a test
loed to mealure leakage current luch that the allowable leakage current Is
the lime for all frequencies to 1 kHz. The allowable leakage current Is
Incre..ed directly proportional to the frequency for frequencies higher than
1 kHz up to 100 kHz. "'bove 100 kHz the allowable IlIkage current is the
lame al at 100 kHz--l00 times the value at 1 kHz. The equivalent de shock

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current for the sime .ffect Is taken I I '0' .arger thin the 10 Hz current.
The ANSI/MMI ("78) test lad II slmlilir.
There Is I question a. to whether the .ffKt on the human body of •
shock from a non-sinusofdal. periodic waveform can be conlldered the lame
..• the effact of uch Individual frequency component .ffect lulIIIMd appropriately. Until further dltl .r. Ivanable, there II no other .IY to analyze I
non-sinusoidal. periodic waveform.

THE ELECTRIC FENCE TRAIN OF PULSE SHOCKS

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The .Iectrlc fence controller (Underwriters Laborltories, 1980) provides
• blsls for determining what i. considered a u" electric shock for I train
of pulse.. The elKtrfc fence has ,been used for runy yurt with the re.llzatlon that humanl will contlet the fence but mUlt not be injured. The controller delly.rs I pulle type output with the output during the ·on time"
being of the peak discharge-type output or of the 60 Hz sinusoidal-type
output. All tests for the controller Ire performed with I 500 ohm 100d.
The ·off period- for the controller mUlt bI grHter than 0.9 I for ..
sinusoid.' type output or greater thin 0.75 s for I peak discharge-type
..
output. This ·Off period· Is ellential to allow an Individual to get off the
fence a. the output during the "on period· is 9ft.. t., than the let-go
current level. Continuous output il not permitted. Any single failure in
the controller must not produce I continuous current grute, thin 5 mA.
The Won period- for peak discharge-type controllers must be 'esl than
0.2 seconds. For this peak discharge-type controller, the output delfvered
to • 500 ohm load during the ·on time· II limited to • give" value of
milliampere-seconds, charge, depending on the length of the ·on period.·
The curve for the Ian period" for peak discharge-type controllers proyldes
allowable milliamper.-second vllues for the tl.... period from 0.03 I to
I.
For ·on periods" from 0.1 to 0.2 second. the IlIow.bl. output II • mA-l.
The allow_bl. output II ,... '.. old to 2 mA-s for _ o. 03 second -on period."
For Iinuloidal-type output the ·on period" mUlt be Ie. than 0.2 s.
For ·on perlods ll betw..n 0.025 sand 0.2 I. the allowable current must be
lesl thin
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I • 7S - 350T mA r.m.l •

(2)

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where T Is the ·on period" in seconds. For "on period" between 0.025 5
end 0.2 I, equation (2) allows sinusoidal type r.m.s. currents betw.. n 65
_nd 5 mA. These vllues Ire well below the 500 mA level consider-=!

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d.ngerous for I .'ng'. shock of such duration. It Is Importllnt to note.
howeYer, thlt the f.nce controller produces I train of pull.. rather than I
..
lingle pul•••
Noting that the pul•• repetition frequency for the sinusoidal-type pulse
Is Ipproxllnltely 1 Hz, the true r.m.s. current can be calculated for dlf-

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f.rent pull. ·on periods" when the r.m.s. value of the current durlnp the
pull. Is ~IY.n by equation (2). The results for pulse width betw..n 0.025 s
and 0.2 I Ire given in Table
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TABLE 1
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Current

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0.025
0.05
0.07

1D.'7
12.1-

13.3' (m_x)

12.'2
1.65
1.9

0.10
0.15

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(I)

0.2

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True r .m. I

Pulse Width (Tl

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True" r.m.s. Current Rellted to Pulse Width

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This Indicates that the highest output current Is about 13 mA which is

above the 60 Hz let-go current for lome individuals.

The current should

"ot electrocute .- person at this level. The... stili is I question IS to
whether the true r."'.I. current given In Table 1 cln be equlted to the
_ffect of 60 Hz currents. The pulse train will h_ve frequency components

1

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Ibove 1 kHz •
To stUdy the frequency

"

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for the putse trlin the Fourier
spectrum (Cooper, "67) for a single pulse Is calculated. Beause the
pul....... periodic with. frequency of 1 Hz, the amplitudes for the Individual harmonics ar. proportional to ~~e value of the Fourier lpectrum It

discrete

frequencl..--startlng It , ~:. and It all higher frequencies .epa-

...tecl by 1 Hz. The peak discrete frequency component II 21' tl..... the
Fourier spectrum v.lue It that frequency where 'f II the period for the
•

Above 1 kHz the .ffKt of the frequency cOmponents on
the hUNn body decr•••e Inyer.ely proportional to the frequency. UIJn~ the
• Fou,.ler spectrum Ind the decr•••e In .ffect of the shock for frequencies
PUIIH In seconds.

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KMwe 1 kHz. the ,.ffective r.m.l. current for the n1th harmonic is given in

I·

eq~tlon

(3)

1•• (7I-350T) T ~Sfn "-10 .T + sin "+10 ~T] •
n
wnw
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where n 1. the harmon Ie and, In th II CIII, Its frequency (n • '.2.3. ---):
T II the 80n period- In second.; Ind the frequency of the slnuloidal output
during the pull. is 60 Hz. Above 1 kHz, equation (3) Indlcltes thlt the
ha....nlcl
IIMII Ind failing off r.pldly 10 that tha frequency components
below 1 kHz .re the most prominent. Thul, the true r.II.I. current values
In Table 1
equlv.lent to .the 10 Hz valu.. I I f.r
.ffect on the humin
- body il cancerned.

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NOVA XR 5000 SHOCKS

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The NOVI XR 5000 hi. In output consisting of • trlin of d.....ped

,Inulolda' pul....
.

The curr,nt output depends on the

.'-etricI' rlslstlnce

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betw..n the probes.

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This will vary depending on the type of contact Ind
.hether the shock II denvered through clothel.
In camparing current level. betw..n the output of the XR SOOO Ind the
previously discussed physiological effects It is Important to take into account
the path of the current. Ventrlcullr fibrillation is caused by current traversing the heart. The XR 5000 hal I very well def1ned pith between the
two closely IPK.t probes. The current delivered to the he.rt will be
negligible. This makes dlsculling lethility using the totll current a technique thlt proyldes In extra margin of IIfety. Medicll Inspection of Yolunt.r. undergoing XR 5000 shocks rey.led no clinically sygnif1cant chlnges
to their E. K • C •
~
The action of the XR 5000 in causing mu!'~I. contraction shows In ICtion
-.ch like the 'et-go phenomenon. In the In, :.:urr.,ts of 5 to 10 mA cIuse
this eff-et.
The XR 5000 I. battery operated Ind unground.cf. Any electricil
current will only trlvel betwH" the two probe.. A use, holding the device
."d contacting ground with his other Mnd will rK.lve no shock. a. he is
not In the current PIIth betwHn the probes.

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Output Voltage Waveform and Perimeters
The output volmge wlveform for the XR 5000 consists of • trlin of
Ullped sinusoidal pulses where each pulse is of the form

,~

v(t) • yo.-t/T sin -d t

•

th. pul.e repetition frequency I. 11 Hz. From oscilloscope traces of the
output vO'bge for vI"ous r•• lstance loads. the parameters In equlltlon (")
un t. ev.lu.ted. The tllM constlnt T. and the frequency, .d' Cln be
....ured directly from the trKe. V 0 II cllculated by finding the t'me, t p '
for the first voltage peak- and the JUgnitude of the first voltage peak, Vp ,

f,

.

V

T~

11

,.... the trllce Ind then using
(5)
,.,

Us1ng the output voltage traces for I~ds of 200, "0, Ind 1020 D, the
"rIm.tlrs Ihown In Tab'. 2 .er. determined.
-

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TABLE Z XR 5000 Output Plramete"
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Load Resistance (a)
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1

....

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1500

4000

(111)

•

T

( us)

•

V

(V)

t

,

p

(V)

200

p

o

1

1000

13.000

10

•
•

2

5000

10,000

17,600

2.5

20aO·

1700

1020

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•

',28 x 105

•

100

-d (,-.:1'5)

•

7X10

'd (kHz)

•

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..

t

Effectlve.Oyteut Cur..ent
Using the v.lu. fram T.ble 2, the
output current for I pulse
tNin of dlmped sinusoid. with a repetition frequency of ,. Hz c.n be ca'cuI.teet and are shown In Table 3.

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TABLE 3

L

LMd Resistlnee (D)
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r.m.s • (mAl

12.'

200

11.0

"0

T'"

_
1'"

.,...

C_lcullted Effective Currents

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57.4

1020
1700
,

The effeCtive current shown In Tlble 3 could be hazlrdous If they were It
I' Hz: however. the output pul... contltin high frequency components which
.... much I~. lethal than 10 Hz currents. I t II necessary to consider all the
frequency components for the pull.. usl"9 a luitabl. weighting factor.
Frequency Com.e!!nents In XR 5000 Output
The XR 5000 output il I t ... i" of damped sJnusQidal pulses of the form
r

v
l'
;

i

(t) • Vo.

-It sin -d t V

(&)

The Fourier .erie. frequencY compon.... ts for the train of damped sinusoidal
pulles are obtlined from the Fourier spectrum (Cooper. 1967) for the single

dlmped sinusoidal pUIH· of equltion (I) and II:

(7)
...••

•

wh. . . . . . 11 T • 105.-1 •

Equetfon (7) can be recognized as
system with the following parlmeters

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second order

5
Undlmped n.tUfll frequency (M ) • (.2.... 2) 1/2 • 7.07 )( 10 rldls or
n
d
Und.... ped natur.1 frequency (fn ) • 112.5 kHz
•
and Damping ratio"( ~) • .'-n - 0.1.

'I

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Since the bandwidth for luch a Iystem
approximately 172 kHz. the
lpectrum hal significant high freauency components within the bandwidth,
but these .... above the 1 kHz frequency 10 the .ff-eta of elec;trlc shock on
the humin body for I given magnitude current Ire reduced.
.
lecaus. the d....ped ,'nuloldll pul.e. .r. periodic with • frequency of
,. HI. the r.III.I. v.lues for the Fourier .erla harmonics .,. proportional to

•

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•

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•

•

9

•

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•

the value of the Fouri.r spectrum It the harmonic frequency.

For this clse

r1

the Fourier series hal Its fundamental frequency of ,& Hz with the higher
harmonics III thl multiples of 11 Hz.
Using equation (7), the r.m.s. value for the h.rmonlc at uch discrete
harmonic frequency,
.

III,

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III

,.

(I)
.."
,I
,
I

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where

f • 1& Hz
"d • 7 X 10

'"d

fit

5

· ·
rad/s

h_1 discrete vllues at

M •

21' (' 6n) where n • 1.2.3, --- •

.
The true r.III.S. wlue for the current Including the first" harmonics is the

sq.,. .-GOt of the sum of the sqUires for the first n harmonic values from
eqUltlon (I).
The harmonics from eQuation (I) mUlt be reduced by introducing the

1i
I
I

frequency response for the human body when the .ffects for shock cur...nts
Ire r~uced proportlonll to f ....qu.ncy for freQuencies betw.. n 1 kHz and
100 kHz. This can b. ICcomplished by multiplying the magnitude for I given
harmonic, n, found In equ.tlon (I) by the factor:

1

-1
I

-

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.

COw) • (1 + (f/105 )2] 1/2 /11 + (f/1 03 )2) 1/2

,
I

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(9)

2
l
2
• (1 + 2.5' X 10· n )1/2/(1 + 2.56 ~ '0-'n )'/2
Combining eq~tlonl CI·) Ind (I) the

".In.I.

value. for 'the current to the
MOth h.nnonic, 'loa Hz, hive been Cllculated and
show In Tlble '.
,

I'.

InclUding higher h.rmonics would not incr.... ·the value "gnlflclntly because

,

of the attenult'on It the high.' frequencies.
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TABLE. Effective XI' saoo Output for Frequency Components
to IGOth Hlrmonic. HOI Hz
_.
(naA)
I
LoN Resistance (0)
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200

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1020
1700

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3.21
2.17
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PRIOR STUDIES RELATINC TO XR5DOO TYPE SHOCKS
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In a r~rt prepllred for the u.S. Consumer Product S.fety Commission
(Bernlteln. "71) • .,othw device Intend... to be used on peopl. and to
d.-lver I tn'n of ~ped sfn~soId.' PU'I.. It I freauency of 13 Hz •••
evaluat8d. Tid. report Ind'e-tH tMt the output ••• equivalent to In IPpro....t11 , InA. 10 Hz shock. A lawr stUdy where the effectl of the different frequency components ..... more .ccurately cllculated showed that the
dwlce output .a. equh,.'ent to In approxlmlte 3 mA, 10 Hz lhock
•
(Iemlt.ln. 1113). These tech"IQua were used in this report.
The XRIOGO is certainly 81 saf. .s the deYlce evalulted for the U. S •
Conlu....r Product safety Commission. In f8ct. It I. .Ifer becau.. the well
defined current r-th betw..n the closely spaced probes of the XR5000 will
Ilgnlflcantly reduce tM current delivered to the h•• rt.

+

1. -

2.
....

T.b.., shows

-

t.~.t

the output for the XR 5000 II about equivllent
to • 3 IliA. 10 HI Ihock. Such. shock I. not dangeroul.
Th. 3 IlIA shock II .t .bout the 'et-go curnnt 1.,.1. The shock
NY be IftOre Inten.. than that caused by such • 3 naA let-go
current In the arm bee.UN the cu rrent denl'ty .t the probes II
.,.ter and because of the ..nutlon ClUIKt by the Iplrk from the
electrode to the skin.

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CONCLUS IONS

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Because the shocking current is only In the ~th between the

3.

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electrodes about 2 Inches apart, the current that might reach the
hurt's much less thin in I IImb-to-limb or In .acrols-the-chest
shock. This adds to the lafety •
The units can be used In I damp or wet environment without
hazard to the us.r. The unit may not work well because lelkage
betwHn electrode., but the o~rltor should not be shocked If he

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keeps his hand In Its usual position •
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REFERENCES
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ANSI el01.1 (1'73).

AmeriCln National Standard for L•• k'a- Current for

~flanc.l. • ~merJc.n

-wiiion.rn.na.,as

rnstrtu&, 'A~ "'Vorl(.

ANSI/MMI SCL 12/71(1'7'). AmerlClin Natlona' Standard ~,. Current
Umlts for ElectromecOcn • ...,atul-. Xssocl.tion for ftl.
vane..." o'
ca
rumen tlon, Arlington, VA.

nl

- ... -

.

Bernlteln ~ T. (, '75 ) • Theories of the caule. of dMth from .Iectrlc Ity In
~ the t_te nlnet.nth century. Medicil Instrumentltlon, '. 2&7-273.

--

.

Bernlteln. T. (19'1) IAtt.r report to Mr. Neil P. Zynch, U.S. Coonsumer
Product Safety Commission. February 12, 1971. Reviled February
7. "77.
1

L

Bernltein, T. (1,e3). S.fety crfterie for Intended or expected non-lethal
electrlca' shocks. Symposium on Electrical Shock Safety Criteril
lponsored by· The Electric Powe, R....rch Institute, The Canadian
Electricil AISOC iatIon , and Ont_rlo Hydro. Toronto, Cllnldll.
September, 1113 •
Blegelmel.r, C. and W. R. L. (1"0).

Considerltlons on the
Threshold of Ventricullir Fibrlilition for
shocks It 50-60 Hz.
"nlt~. Elec. Eng"s., 127. 103-110.
New

_.c.

rroc.

MethodS of S!9nar and-h'stem
Holt, Rinehart and .Winston, Aew tofl<, pg.

Cooper. C. R. Ind C.

Anll;tsl..

D.

,

McCUlem (1'17).

m:-

Dllzlel, C. F. Ind T. H. M_nlfleld (1 150) • Effect of Frequency on
Perception Currents. Trans. Am. Inlt. Elect.
&"

1112-1161.

••

Ens,•. ,

p.rt 2.

Dalzie., C. F. Ind F. P. MaII09IlI (1'56). Let-go Currents and VoltBges.
Trani. Am. 'nlt. EI~t. Engr•• , 75, s-rt 2, 49-56.
Underwriters Laborltorf. ('972). UL 943, Sundard for S'f~
Cround-Flult Circuit Interrueter, pg. 'TCI: revT.eif""J'inu.ry 7,

'l1'1"•

.•

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Underw,' terl Labor.torie. ( 1971) • UL 5", Stlndard fo~ Safe~MediCI. and
Dental Equle!!!nt, 2nd ed •• pg. 31, revlliifJanuary • "".
-.

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Underwriters Lllbor.torl. (1'10). UL I', Standard for Safe!lr.. Electric
Fence Controllers, 5th ed •• pp. n:Tf:
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UNITED STATES GOVERNMENT

u.s."

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CONSUMe~

O,'\~E OF ., .:

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SAFETY CCMMIS~IOi'

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Memorandum

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IftIRU ; J.1argaret F~eo5ton, ASS~/•.I.~cnera.l;,.C~:u.n~~::"JCT
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Jeanette

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~CT: Jurisdic~ion
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SAfEty

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the Taser Public Defender

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-The Consumer Product Safety Act gives the Consumer
Product Safety Cc~ission jurisdiction over all consumer
proaucts. The ter:n "cQns~cer product" e:ccludcs " ••• any
article.which, if ~old =y the manu~ac~wrQr, produ=er,
or importer, wo~ld be s~~joet to the tax impoSQd. by
•• C~iOD 4181 of the Int~:nal.Revenu. Cede ot 19S4 ••. cr
any component of an~' such artie,le .•• " (15 U.S.C. 2052 .
(a) (1) (E».
Sec~io~ ~19l includes pisto1s, revolvers,
fir.a~s, shells and cartridges.
(Emp~asis add3c)
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·The question is \11hether the "Taser

is a firearm
wi~hin the meaning of section 4181 o~ the Internwl
Revenue COCB (25 U.S.C. 4rBl) •. The te~ fireD~m has
bean defined in 18 U.S.C. 921 (Gun Con~rol ~c~ of
1968), 15 U.S.C. 901 end 20 U:S.C. 58'8. It is not
clear which de~inition is ap~licaDl., however 18 u.s.c.
921 is the mo=~ comprehensive.
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The term -firearm" means CA) any
weapon (includinv a .tar~.r qun) which
will or is desiined ~~ or mav teadily
be conver1:.a 1:0 exoel a ..2rojietne E;j
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'Die .taction o'! an .iC~tXO.1V.f'(B) the
rrame or receiver of any such weapon;
·(C) any firearm muffler or firearm
•
.ail.ncer: or (D) any destructive de~ ·,v1ce.
Such term 40es not include
· 'an ant.iqua firearm.
(E¥DPhasis
added)
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(3)

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(4) ~he
.ana-

t~ ·4estruc~ive

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devic.-

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· CA) any explosive, incenc!iazy•
or poison gas -

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(1)

bomb,

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(li) grenade,
.
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(111) rocket'having a propellant: charge of lIlore than
four OUDces,

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(iv) missile having an explosivG
or incendiary charqQ more than onequarter ounce,

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(v)

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mine, or

(vi) device .~ilarto any of
the devices described in the preceding clauses:

any type of weapon (other than a
.ho~9un- or a shotgun sb~11 which t~e
S.cre~ary ~inQs. is qene:clly recc9ni.e:
a. par~icu1Drly suitable for sportiny
purposes) by ,.,hetever n!1:r.e kno\nl \olhich
will, ·or which may be r.adily conve:ted
~O, e~~.l a.projectile by ~e.action·
of an' explosive or other propell~nt,
(B)

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and which

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of more
and

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tla~ any barrel \o,ith
than one-hal~ inch in

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a bore
diameter;

combi~ion of part. either
d.signed or in~ended for use in CQn.·ver~ing any 4evice in~o any des~ructive
device d•• cri~.d in subparagraph (A) or

(e) any

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(B) and from which • destructive device
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. .y be readily ••• embled •
•
%D r ••ponse 1:0 an inquiry from Mr. J.E. Rogers· of
Be,ers, Mirabelle' , Derlanti a.ted 10-12-73 concerninq the
classification of the ·~a••r· under the provisions of ~he
Gun Control Act of 1968~ y~. A. A~l.y Peterson, Assistant
Dizector, Technical and'Scientific Services, Bureau of
Alcohol, Firearms anc! Tobacco, Depar1:ment of the Treasury
cODcludeC! ~J'1e following:
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Ce -T••c· i . Dot a firearm all a.fined
...lD 18 D.S.C. '21. Rationale- Although the
·~.s.r· w~r.. are expelled by ~h. explosion
or expansion of ga.es generated by ~. ignition
of 4/5 of a grain of smokeless powder, the wires
° ana appropria1:e wire contActs do not meet the
. 4efinition of a projectile. The determinwtion
1. based on the fact that the muzzle velocity
1. well below ~he standards established by
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oil

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the Office of the Surgeon General,
Department of Army. Research studies
conduct~d by th"t office indicate th~t
an impact velocit~' of from 125 to 170
feet per second, contin9~nt on the
composition and sh~?e of the projectile,
is neCQSSilry to c"use a break in the skin
.in an unclothed area. These findings
- reinforce the finding of ATF that the net
or barbs are not projectiles since they
· deploy ever a strictly limited area nna
are still attwchec to th2 basic como~nent·
by means of the wires. which convey the
electric ch~r;e.·

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This office aqrees with the findin;s-of the Alcohol,
Tobacco and !'irea=r.~s Division o~ the neper-:lnent of the
Treasury and co~c:1.i..:Ca5 thG t .-the Tase:" does not fall \-:i thin the purvie~ of seeti~n 4181 of the !nter~al Raven~e
Code of 1954 (26 U.S.C. 418.1):: Since tlla "'raser" ~is not
specifically excl~Qed under the CQns~~er Produ:t Sa=et~'
Act, the Co~~iss~on can a~ercisa jurisdiction over th~
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product under that Act.
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While the views expressed in this opinion are based
OD

the

IIlOS-t

current

inte~retation"of

the law by this

office, they could subsc;uently be changed or superseded .
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STATEMENT
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The

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Co~sumer

Product Safety

Commissio~ has

received the opinion of the Bureau of

Aleoho~,

Tobacco

~=easury)

and Firearms (within the Department of the
...

today

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regarding their decision to regulate the TASER under the
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Gun Control Act of 1968

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~he

Commission is presently reviewing ATF's opinion

in view of an earlier CPSC vote declaring the TASER a
consumer product which could be regulated ,by, the Consumer
Product Safety Act.

It is too • soon to determine what the
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implication of ATF's decision.will
be
regarding
the
. .Commission's earlier decision.
The Commission will delay action on a currently
,

pending petition from Mr. Michael Lubin,

Wa~hin9ton,

D.C.,

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requesting the Commission to set stancards or ban the
TASER under the authority of the Consumer Product Safety
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Act.

No timetable has been set for a Commission cecision
· on either

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ATF opinion or the Lubin petition.
-30-

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3/18/76
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UNITEC STATES GOVEFlNMENT

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U.S~

A
'-/

"-:!~._'.:'-~-

Memorandum

CON5UME;::::1 ~~=:JUC:T
SAFETY C='''~'.. ·,SSiO~

WA.SHINGTON. 0 C. cC207
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OATE=

Technical Analysis Division

: Neil P. Zy11ch, Hazard Analysis ~nEi~eer
Special Eng1neerins Studies Division
.

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Joseph Z. Pandey

....

SU&Jl!CT:·

TASER Evalu.at1on and Analysis

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The Bureau of Engineering Sciences ~as requested by the
Office of Standards Coordination and Appraisal to evaluate
the TASER Public Defender tor potential tor injury •

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DESCRIPTION
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The TASER is a battery operated dev1c-e the size of a large
flashlight (dimensions are 9 tf x3"x2" and weighs 1-1/4
pounds). It contains a cartridge-like insert that when
ac~uated by a s~all c~ar6e or po~der, propels two small
darts. Each dart is conneeted by'a'wire 18 feet in length
To a tr~rormer power source within the TASER. When,
the darts are propelled, it they strike either skin or
clothing they will 1rebed themselves in it. It both darts
imbed themselves in either skin or clothing on a person,
the person can be sUbjected to an electrical shock.
Note, the darts do n~t have to make physical contact
with a person but just attach themselves to a person's

clothing in order tor the person to receive an electrical
shock. The holder ot the TAS!R depresses a Iw1tch on
the TASER after the darts have been tired and imbedded
in order to transmit an electrical shock to the intended
victim. The electrical shock lasts as long as the switch
is depressed. Approximately two to three minutes is the
maximum time duration the electrical shock can be applied.
continuously before the battery is discharged and the
TASER becomes ineffective.
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at:.CI:.J V£0

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[

FEB 191976

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is'hICAL Ar~AlYS\S ~

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Subj e.ct :

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tIiIIIIIIJl- ..

~valuaticn

and Analy!is

BACKGROUND

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DES throu~t C~~A cbta1~ed ~:c ~A~ERS, a circuit descri;t10n of the TASER, and test and operational literature
on the TASEn. After an initial review and analysis of
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the TASER by BES (\oJh1ch' included taking photoeraphs
·ot the TASER output ~avetor~ at various impedances
which simulated body 1~pedancej see Attachment 3) it was
~ec1de~ to concentrate on the electrical aspects of the.
TASER only~ The 1njury,errect or the pointed darts was

,

•

,considered. It is concluded that the barbs will penetrate
human -skin to a maximum depth of approximately 5/16".
The most obv1ousserious injury which could result from
the dart itself would be an injury to the eye •.
BES contracted with Dr. Theodore Bernstein ot the
University or Wisconsin. a recosn1zed authority in the
tield ot electric shock etreeta, to evaluate and analyze
the TASER electrical output. ,The TASER output waveforms
were measured at the National Bureau ot .Standards b1
epse personnel and photocraphed. '!'hii information" a
TASER, and literature made.ava11able by the TASER manutacturer concerhing the t&St1ng and safety or the device
were supplied to Dr. Bernstein ror evaluation. _-...m

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BES haa reviewed Dr. Bernstein's analysis, a copy ot
which is attached. Attachment 2 contains specific
comments and/or claritication concerning this analysis.
RESULTS
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The calculated efrective current to which an Individual
·would be subjected 11 approximately ten milliamperes.
This current 1s above the threshold ot the "let 10"
current value in the literature tor which teat data is
available. Protessor Dalziel-reported on tests conducted
on volunteer sUbjects: -0' or the women tested and 15S
ot the men tested could not let loot a current in excess
of 10 mae While this value caused pain. no permanent
injury resulted. These teata were conducted at 60 hz.
It should be noted howevertbat ~h. ettect ot let 10
1. a function ot frequency .a well as current. At
frequencies above 100 hE the errects or current decrease
auch that the let go current increases. 'or example
the titty percentile let 10 threshold tor men at 60 hz
1. 17 ma While the tifty percentile let go threshold
tor men at 10 khz 18 7- mae Thus the 10 khz threshold
is over tour times as h1;h aa tor 60 hz.

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the University or California, the
]ead1nE authority in this field prior to his

'Proressor Charles DalZiel
reco~n1zed

rec~nt r~t1r~~~n~.
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TASER Evaluation and Analysis

Subject:
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Dr. Bernstein states that the "tr.axirr.u:n TASER output is
APproximately lOr. or the lethal value". This rel"tes
the value of rms current for all rre~uency compone~:s
up to 13 khz or approximately 10 ma to the cc~~only
accepted value of 100 ma for ventricular fibrillation
· or a normal adult hu~an. ProfeEsor Kouwenhoven in his
paper on "Erfect or Electric Shock" in the Transaction
or A.I.E~E. V.~9, January 1930, p. 381 stated ttat
100 m1111amperes may cause death and that for norwal
persons the current should not exceed 30 milliamperes .
. Ferr~s, Spence, Williams and King stated in their report,
nEtf'ec"t or Electr1c Shock on the Heart" in Electrical
.!ng1neer1ns, v. 55, May 1936, p. ~98 that the max1rnu~
current to which man may safely be subjected. tor shocks
or one second or more in duration is about 100
1I1111amperes. Dalziel and Lee have shown with tests
on dOIS in their report. "Lethal Electric Currents"
in the Pebruar, 1969 IEEE Spectrum on Page~8 that the
averase 100 pound or more animal requ1~es approximately
100 ~111ampere. tor ventricular fibrillation.
B. Spencer ~er in his report on "Human Responses to
tlectr1c1ty A Literature Review", Ohio State University
Research Foundation. 1972 on Page ~3' states that sinucurrents In excess~r 100 ma at 60 hz trom hand
to toot will be dangerous tor shock durations ot three
a.conde or more tor man •
•
With regard to establ1sh1nc a standard tor such a device;
81mpll stated, a standard would address such deVices
tor both AC and DC operation.

"

!be enerlY output ot such dev1ces would·bave to be defined
1n terms ot trequenc1, puls. be1sht. pulse Width, on
and ott t1me ot puls.a. !he maximum energy would then
have to be determined tor various frequency bands such
that at least the 30 dispersion ot the population would be
covered. The definition ot the energy l,vela would
depend on medical Judeementa. and Whatever data may be
available 1n the literature.
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Subject:

TASER Evaluation and Analysis

.

CC:'lCLUSlcrr

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In conclusion J BES agrees with the finding that the TASER
should not be lethal to a normal healthy person. This 1s
. based on a comparison or Dr. Bernstein's engineering
results with the known engineering data 1n the literature.
A4d1t1onally a standard could be developed but not
without a costly and time consum1ns program to do so.
530959:76:NPZy11ch:pc
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DEPARTMENT OF ELECTRICAL

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AND COr.tPUTER ENGINEERING
1425 Johnsen Drive
Mldison. Wi,consin 53706
Telephone: 608/262-3940

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February 12, 1976
•

Mr. Hei1 P. Zylich
Hazard Analysis Enqineer, BES
consumer Product Safety Commission
5401 Westband Avenue, Room 918
Bethesda, Maryla~a· 20207

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Dear l-tr. Zylich:

I have completed my analysis of the information you sent me with
your letter of February 4-concerning the ~aser Public Defender electric
gun. The primary emphasis in ~y study was to determine whether the
Taaer electrical ou~put can be lethal. I did not deal with other pos.1ble hazards ~h.t would probably be non-lethal such a. electrical
, burn. or physical injury cau.ed by ~e dar~••
~he

~

electrical output for a aevice i . a function of the load on
, that device. The Taser output was ~•• ted with resistance loads of
200, 500 and 1000 ohms as well •• hiqher resistance loads. I perfo%1T"-:--·d
Done of these tests but have evaluated the test results. With the
, Tesar darts fully inserted into tissue, ~he exposed dart area per dart
._. ~ula be about 5.5 mm 2 • Geddes :B.Dd Baker show impedances betweeD- pairs. of needle electrodes to be approximately 1000 ohms for 5.6 mm 2 exposed
_, .zoe. electrodes and approximately 300 ohms for 73 mm 2 .1ectrodes.
[L.A. Geddes and L.E. Baker, Prine! Ie. of A lied Bicmedical Instru· JDent:a'tion. New York: John W ey, 1 7 , PCJ. 48.
S1nce the Taser
.e ectro es have barbs and are forcefully inserted, it w~uld seem that
loccl trauma would increase the eff.c~1v. area of the barb and ~us de~
cre... electrode r •• i.~anc. 1:0 -the 200 'to 1000 ohm range. .
.
.
'
~•• ~ were conduc~e4 to 4.~~n. the T••• r ou~pu~ in~c 200, 500
and 1000 ohDI r •• is1:ive loac!.. 'fhe output consisted of • train of dampec
ainusoid.
with.
frequency
for
the
pul•••
of
13
Hz.
One
possible
means
•
for evaluating the safety for the Ta.er ou~put is to compare the output to the output of • device that provide. shocks tha~ are considered
.afe for humans. Appendix F supplies • summa=y for the maximum output
,
for an electric fence controller in~o a SOO ohm 10a4 as specified by
Underwriter. Laboratori... It i • • •en that pul••• with an energy ~f.
approxiJlla1:ely 90 mJ per pula. 18 maximum. The maximum pulse repet1 tl.on
, rate 1. about 1 Hz - off period .ust be gr.ater than O.1~ secondS. In
~ Appendix A, ~h. energy per puls. fo~ ~. T•• er w•• calculated for 200,
5a~ aD4 1000 ohm loads.
~he r.sul~. were:
1

•

,

..

•

500
1000

•

•
102.2

140

...

•

•

.
II

•

•

....

•

,

•

•

•

...
•

I

--------------------------

L
L
L
•

L
L
L
L
[

L
L
L
L
L
L
L
L·

•

.".nz.",.in••'

m··F1"'lPttlll:rnilllililliiillfilolilrf_ _..,

•

•

Thus ,the Taser output energy per pulse is sor...:,..hat. higher than the
a11owal:>le out.put for wn electric fence. A ::'.ore i::lportant. Foir.t, l-.c~;ever
is that the Taser pulses occur 13 times per seccnd cO~Fared to ~he c~ce
per second for the fence. The power into the load is then 13 ti~es
greater for the Taser output than for the elec~ric fe~ce. ~hese ~esults
indicate that the Taser output is more hazardous than an electric fence
output.
.
Secause the Taser output consists of a pulse train, it appears
best to compare this output to the known effects of steady state sinusoidal currents. Much work has been done on the effects of different
value.'of effective, rms, currents and on the effect of different frequencies. In Appendix B, the effective value for the Taser output
current is calculated. The results are:
•

Rx,CQ)

I rms (rnA)

I

•

200

60

500
1000

51.6
42.7

,

For 60 Hz, alternating current, the current that will cause ventricular
fibrillation in one out of two hundred individuals is greater than
approximately
• 150 rnA
IJ:1IIS

,#j

where '1' is in seconds. This expression is valid for 8.3 ms < '1' < 55
with the value of current from 5 . to
20
seconds
about
the
same
as
for
5 .econd~ The .onstan~, lSo-i.-.ometimes reduced to 100 when considering safe current levels for children. The effective current output for
the '1'aser appears to be close to the 'leve1 that can cause ventricular
fibrillation and death except for the fact that the heart does not respond readily to higher frequency currents. The lethal level for 60 Hz
current cannot be compared directly to the total effective current
output of the '1'aser because the Taser output has high frequen~y components that have negligible effect on the heart.
•

, '1'0 include the response of the heart to the frequency of the
electric current, the frequency spectrum for the '1'aser output was calculated in Appendix C. Appendix D provides a calculation for the
effective value for each of the frequency components for the Taser output, in addition, compensation is included in the calculations to
inclUde the fact that higher frequency components have less effect on
the heart. It is shown in Appendix D that a conservative approach, one
that maximizes any danger, is to assume that the heart responds equally
.~ all frequencies of current to 13 kHz and does not respond to frequencies above this value. Taking equal magnitudes for all frequency
components below 13 kHz in the '1'aser output and with. 13 kHz cut-off,
the following effective currents were calculated:
•
I
(rnA)
Rx,
rms
•

L
L
L·

'fio

8.9
8.7

500
1000

10.9

•

•

,

•

'I ~

i

•

'"

.
.
~hb. it appears

r
,
.
ma~im~~ Taser output current

that the
i~ c~Froxi~3tcly
10' of the lethal value. ~he current is a~eut t\~iee the S ~~ l~t-~o
current level which seems to explain why the shocks are effe'ctive in
incapacitating an individual.

Appendix E includes a discussion of the Taser provided test result!

ana references.
..

. 1.
2.

Conclusions

.

•

•

~b. ~•• er

electrical output is not lethal.

with any elec~ic shocking device, there may be eases of
lethality because of individual susceptibility.

As

3. The hazard in the
~10D

outpu~

would be increased if the pulse repeti-

rate should increase or the amplitude of the output increased •
•

,

Sincerely,

..
.,

(

.

Dr. Theodore Bernstein

..
..

.

Professor

•

TB:aeh
•
•

•
...

..

+

•

--

-

~

.

•

•

•

•
•

•

•
L·

•

.

•

•

•
•

•

•

..

•

•

• •

•
•

iI
1

I
~

r

~

•

.

APPE:~DIX

A

Enerqy Content in Damped

Sine Wave pulse

Consider the voltage waveform as in Figure Al ..~cross an R ·
·ohm load
.
1

t

Voltage

•

•

(s)

(V)
...

Figure Al
"

'this curve can be approximated' by
•

Vo. ~
~

.~

vet) •

sin Cddt
•

...

(Al)

V
..

GJ!re 1 is the time constant for_the aampi n 9 term in seconds and
..-..

_

.~

w

.
•

"4 is the damped natural frequency in radians per second.

L

The instantaneouS power delivered to the resistor is
oil

2

,

P (ot) • .,

V2

_ 2t

~

itt • .:.

s1n

2

"4~

(A2)

w
..

.

..

while the energy 41•• ipate4 1n 'the re.i.~oz is
W•

I

•

• v2
p (t) d t •

o

I : . ~. in

2

Cd clt.

d~

(A3)

0

2
1
Since sin A • I (l-cos2A)
I

_ 2't

2

•

•

[DWi9ht 404.12J
.. 2~

. . . 2t

(A.)

o
From Dwight, 577.2
ax
I.

.ax
COS\lX

dx •

(a

+ \J sin\lx)
I

•

..
-

..

cOS\JX

•

· 11.,
.

.

•

•
I

So

,

...

..

w-

e

e

2t

2

V0

-

2R

t·

-2

t

4 +

~

..... """1

...

~

oil

•

2t
~

-

~

4w~

(-

2

t

eos2LrJdt + 2wdsin2~.t)
.
Q
....

d

0

.

evaluate V ' find the ~ime, ~p' for the first voltage
o

peak anc! the 1Da;n1~ud. of t:he fir.~ voltage peak,
•

vol~.g. 'trace.

vp '

froID the

'1'hen

v
where V is the first peak voltage.
p

•

•
(A6)

+

Thua measuring

vp '

tp'

~, and -4 from ~. voltage ~r.c. p.~i~. th~ calculatioo of
•

Yo·
When, in .quat.ioft (AS)

.r

1

.~«

•

•

1

· i + cateS

L
•

W ..

2
v

'r

(A7)

0

4R

•

•

..
•

•
<

•<
(

~

•

•

....
•

J't

t•

I
I

!

i

I

I

..

'.~

.

III

•
•

•

•

For Taser 1
•

R(O)
•
•

..

Vp(V)
Cd

•

4

SOD

1000

1250

3000

6000

2T (rad/s) 4.83xlO
T
to

~

200

•

•

(.)

....

tp<.)

•

/

,
,

...

5
4.S3xlO

S

4.83x10

5

20)(10- 6

15)(10- 6

5)(10- 6

3xlO~6

3)(10- 6

6
2.5)(10-

1463

3692.

10,583

.(J)
•

..

--

.-----

~

.

•

•

•

•

..

•

•

•

•

•

..

•
...

•

..

.

•
ill

•

•

•

•

•

•

..
•

•

•

.

'-

...

•
•

APP!:NDIX B

Effective Value for

Dampe~

Sinusoidal Pulses

Consider a train of damped sinusoidal pulses a. shown
•
.,.

..

•
.

•

"Jllgure B1
•

T
.

For this train the time constan~ for the pUlse,1i, is much less
•

...

than the pulse repetition rate, T.
.

... t.

V

If

.-

!. :

~ sin

•

fd

(81)

A

t
4

•

then
.•

•

"'~

!~ I

_ V2

o

_ 2t . ~

o.

~

i2" -,.

2
... in

1/2

"

(82)

A

, 4:
II)

t. dt

•
...

for
T

«

'1'

•

U.ing the same -technique .s us-eel for solvin9 equat.ion
•

. 1/2
1

I rms •

T
- l-Hd·2t
c!

(A3)

•

(83)

A

•

As

in

A(7)
#IJ

Vo

t'

1/2

II

•

%ma • 2R i

(B4)
~

~or

1

1.69110
a frequency of 13pp., T •· I
1 I·
a(o)

•

%naa (A)

--2

a.
•

•

500

1000

3
51.'.10-

3
42.7x10-

4

•

, 1,

+

•
- ........

•

•
•

•

f

l-

-

•
•

-

APPENDIX C
•

.

Frequency

,

Componen~s

in Taser Output

For the 'laser out.put shown in Appendix S, Figure Bl,

•
•

•

each of

~he

pulses has the

fo~

•

v
The ,pulses occur

a~

(el)

a frequency with a period of T'seconds •

...

The Fourier

'lrAnsto~

for the sinvle pulse is given by
(C2)

.

..

has a frequency spectrum a. shown in Figure C1.

~.t

I

-

Ip(jw) I

•
+

•

•

•

•

-----

•

&

•

•

•

•

•

•

Plvure «:1
.

.

[G.R. Cooper and C.D. McGl11em, Methods of Si9na~ a~-!ystem
Anal sis. New York: Holt, Rinenart ana winston, I~~
pg.

•
..

!he discrete value. for the discrete

for the periodic s19na! with period

~

. .gnitude of the frequency spectrum

.~

are

~·equency

components

propor~ioD.l

discrete

to the

in~.rv.l.

of

(C3)
..

•

la.ference Da~a for Radio En ineers, sixth edition, pp. 44-10
an
•
~

.
+

•

I

,.

.

.
•

For the outpue of Taser 1

·
R(O)

4.83)(10

Cl)4(rad/s)

1"000

SOD

200

5

4.83)(10

5
4.83)(10

5

•

•

/

•
1

• •

I

lid

.

(kHz)

f d -. 211

~

76.9

76.9

76.9

~

I
r

I

20
•

[

•

Rewriting equation (C2)·
..

.

110:

"

•

.

-

~

(C4)

oz1
...

•

•
•

•

..

where

(CS)

•

[.

(C6)

1 -

(jed)

+ 1

•

•

•

•

..

..
•

.-

•

•

as t11e ! r c·~ ....:a::-'Cj' r cs re~s e

Equation C6 can be

,

secc~d

characteristic for a simple

syste~ ~ith

orear

an

un=a~~ec

natural frequency of
lain •

•

•
a~d

w~)Js

(.2 +

(e7 )

•

a.damping ratio of
a
•••
.

· w
n

•

•

(CS)

Substituting for the values for a and w.Q for each of the loads,
•

R(D)
".

c:

500

1000

0.14

0.38
5
5-. 23)(10

5
4.88)(10

"11 (rad/s)

•

+

...

77.3

.
.

...... 77.. 7
.-..

~

.... .-.

~

83.2

•

..

•

.

•
•

•

..

•

••

•

•

..

[

•

•

.

....

•

•

,.

•

.
•

..

•

.

•

,.
,.

• •
•
•
•

-

I

•

..

.. i

.
.,..
•

~

•

.

APPENDIX D

•

,.,

...1te1ationship Between the Frequency Components in the Taser Output

. .
"

•

"

.

•

and

.
'II

•

..

Human Lethality Currents

•

c.

+

. . !'he Fourier transforms in Appendix

show that the Taser

has a frequency response .spectrumcorresponding to an un-

ou~put
~ped

J!

..

•

•

second order

•

sys~em.

Figure D1 shows

~he

frequency response

•
"

••

+

~ectrum

•

..

•

for the damped sinusoidal pulse with a 2000 load on the
..

'II

...

"

Figur~

'1'aser
•
..
. •

D2 shows the frequency response spectrum for a 10000

"

•

I

Becaus. of the 13 Hz

.load.

•

&c~u.l
I ..

output

~epetition

II

con~iD.

rate for the,pulses, the

I

•

discrete frequencies

wi~_an

frOID the frequency spectrum curve at: discre-te frequencies 13 Hz
,
apart.
•
•
•

~"'I

.
____~
.. ": :.~

•

.'" I

. .." ..

If t:he

,
..... ..

...~~ ,
•:.~. Z1ILS

"..

rIllS

.~~

current for

nth harmonic

is In rms' then

.

current for the

fir.~ N

harmonics is given by

':.

..,.

"Is

..
,.

I 2

.
,,'
.
.
vh~.

.•

..

•

l1li.,

if

1. th~ repetition period

~ curren~
.•

of~the

. ..
...
..

•

•

"~J:Jaat:

.

•

•
~

~

..0

.· .. .
•

campon.n~.
,r

and
•

to

fe; shows
~• • 'tb

G(jCII)

tha~ Cur:.D~

~.t

components

.~

higher

~o

·

fr.~enci•••u.~ be

~

larger for

~h. Association

:'fo~ the Advancement of Medical Instrwnen1:atioD (AAH%) mad. use of

+

•

It is known

higher frequency currents

.. -t'".J:ha same effect a. foJ:' lower f:equency components.

I

harmonic

the frequency

1. relatively' flat to about 40 JcBz.

the buman body i . 1•••••nsit.ive

~

•

that -the

repetition frequency •

responae for
•.

tJ .)

Observing Figures Dl aDd D2, it-i. seen
.

.

.

r

1. for all frequency

(If •

•

..

.1

(Dl)

n~

•

.

.~

•

l1li

•

amplitude reaa

•

t.his when they developel! a ~•• t 10a4 'to test, equipment.

This load

It

It

•

i

I

I

.

..
...

-

•
I

.:1mulated tt a• human

I

body b)' having a frequency response for current

I
I

I
)
i

..

curren~s,~o

that was flat, did not attenuate

Th~

1 kHz.

input cur-

i:

~
~

~
(

~

rents were attenuated inversely proportional to frequency from 1 kHz to

t

100 kHz; at 100 kHz' a current had to be 100 times larger than at 1 kHz fc
•

.~.
•

From 100 kHz and higher the current was attenuated

same effect.

.~

the same value as at 100 kHz.

~.

sbown

a~=~d

This attenuation characteristic

to G(jw) in Figures D1 and D2 to provide an overall

ln41cation of the effect of frequency on the hazard current.

Both

•

-

~

of these curves show that any frequency components 9reater ~han 10
•
"
kHz are attenuated by greater than 0.1. [The AAMI load·was discussed
.

by Denes Roveti, -The Chanqing Face of Electrical Safety:

Test

•

Loads,· Medical Electronics and Data, Vol. 6, No.3, May-June 1975,
pp. 42-45.]

Because of the rapid
con.erva~ive

10 kHz, •

•

•

•

at~nuation

of
effect
of
,

curren~s

above

approach;:an be used where all frequency
.

components up.to 13 kHz are weighted equally while frequency components above 13 kHz are neglected.

•••umed that .11

compon.n~

For the 200n load it is

to • frequency of 13 kHz have the same

Prom
equation
.

Mgnit.ude .s at low frequency.

,

(CS).
•

.
(D2)

•

Using the values of

S
Vo • 1463 V, Ma • 4.83xlO rad/s, R • 2000,
4
an4 • • 5x10

[-.

•

5
I(~o) • 1.531.10-

[
•

•

•

•

•

(D3)

•
,.

.

•

•

•

•

,.

•

~

~.
9

•

•
...

.

I

/,/

•

•

,..I

•

.I

•

..

II

•

.

..

From page 44-11 of Reference Data fer ~3dio En9inee~5, Si~~h ~dition,
•

•

the xms value for a frequency component with the ~a9nitucc

as

given in (D3) is

.

I
•

where

[

i

2

nrms • I2'T
9

is 13 Hz.

So

I (jo)

•

.

•

-

• 2.82)(10-

4

A

•
r; ms
There are 1000 discrete frequency components between
0
and
13,000
•

I

•

Hz so according to equation (D1)
•

I

%1U

•

(1000)~(2.82xlO-4) • 8.9 mA

In a.8tmilar fashion the rms current for all frequency components of the ou'tput.

[

1:0

13 kHz i . given below assuming at all fre-

•

quency ccmponents are equally .ffective ~o 13 kHZ •
.

_

...

%rms(f<13kHZ) • 8.7 mA

R
•
5000
.

a•

.....

d

..,

•

I~(f<13kHZ)

10000

• 10.9 rnA

•

•

•

•

..

......

•
•

•

•

•

.

..

•

•

•

I,

•

., ,

..
•

L~
..

'\.l

Dlscussion·of Physiological Rc'cr~ees

•

Suppliod

~

r

Taser Rc3at!ng to Safety
•

1ft the packet of material supplied by Mr. Neil Zylich with his letter of

I

Februazr
4.1976 only two of the.items relate to the physiological effectscf
.

•
""'!

electrical sbeck •• related to .afety.

These were item 6, T••• r

r.late~ test

•
,

• ~ (dated
•

~y

10, 1972 for T••er 5y.tams, Inc.) and item 7, A -Medical
.

Bibl!ovraphy and SlDIIm&ZY

w

(from TIER. Systems, Inc.).

•

Other material in the packet

....

.uch . . ita 5. 1 A ·Suaa&zy of TAlER Effec1:iven••• - tests (fr01l\ TSER Systems, Inc.)

and i~ 8, Aft -Evaluation ofTASER Effect on Trained Monkeys- deal primarily
with .ffectiven••• and. oDly 1n4i.recUy relata to ••fety because of the qualitative
MmaU 1D which

-.
."

•

•

the t •• U vex. perfoaaed. '

.

...

-,

.

. .

In it. . 6 the statement i . . .de th.t~ -'the desigft ou~ut of the TASER is Ifto%'c,
"
• .
.
.
SO-tJ..au-.lowex than 1MXimUll .af•.1V.1 as determined by .edical tests.· I

-~
doD'~

understanc1 vha't par_tar of the output i . 1/50 of what safe leyel.

stated

th.~ ~.

It is

T. . .r output is clo.e to the operatinv level of electric fence

GDe 'l'uu pulse !au approximat.ely th_ energy allowed for an electric

cnatp\1U.

·

•

fence output bu't t:his h s . suppli•• the•• pul••• at • ~.t. of 13 Hz while the
•

electric fmlce hu a

• 11owu.l. pul••

ou~u~

rate of awroximauly 1 Hz.

In

one second the -ra••r supplied 13 tim•••s much eneZ'en a. an aI.cule fence output •

...

In the effectiveness summary, reference w• • •acSe
•

ac a.c.

90] of 16 InA at 2.5 W cSet.rminecS

t.o, -fr•• zing- level

•Bext.ley :In 1968.

(i.e-

lfhi. fi9U%. refers to

60 Hz tes"'- and d~es not apply directly to the tt••• r type pul•• outvut.

•

·Cndel"Vrit.er
III

•
:w

!.aboZ'awl'l•• in their sUndar&! for .1.etr!c·• fences, D.L. 6', E'ereZ'
~.,.tJ.1:iOIl

1•••

~h&n

rate of .pproximately one per ••cond or ac output with

0.2 • and aft off period of0.9 ••

Great care

.u.~

U)

aD

pulses at •

on period of

be us.d before applying
•

the•• results for the T••er type

Oy~put•

•

•
...
L

i

.

]

.......l

•

I

,

"

In the section on non-lethali:y
of I

It ~

reference is made to an

latin9 shock.

This relationship was

to 60 Hz shock

~i~~

a valid

detc~ined by

range of 8.3

t~e

~~

Prof. Calziel and applies only

to 5 s.
•

.

periods' le•• than One half
•

"be

t~pression

0.1 for t.'1e currcn~-time :"e:l&tionship for the threshold of non-f-ibril-

•

,

s~~~3r"

of A 60

~ele

Hz

It can not be used for
•
•

wave, 8.3 ms.

This relaticnship cannot

used-directly for the Taser type output. A mistake has been made in quotinq a

figure of 4 =A-s cutput as sAfe according to Underwriters Laboratories •• In O.L. 69,
Graph 1

~D

page 18 shows that a

of 4 rnA-a is allowed for shocks with a

max~~

.

pulse on period of 0.1 to 0.-2 s.

For shorter c5uration shocks the allowable value

..,

1s

~eauce4,

i.e.,

~or

a pulse duration of 0.03 _, the allowable value is 2 mA-s •
•

."

'file '1astlz- with its vary short pulse duration would have an evan lower value.
•

•

Once

a,aiD i1: 1. impcr1:ant: t;o note Ulat the U... L. 11:andarcS allows about: one pulse per

secona compared to
.....

T••• r'. 13 pul••• per .econd. -!he reference ~ NIH
..
sponsored studies at Statham Labs isn't-sufficient
for.e
to
find
~is information •
..
~.

.

Any tests eust include

,

.-..

carefur-me&.ureme~~of·e~ica1-pa~ameter.~o
•

properly

\

evaluate such tests.

/

•

It.. 7 b.. the medical

~iblio9r.phy

aoll~ ~est.l

fibrillation telU,

and sunnary.

In sect.ion I on heart

4eal with 60 or 50 Ra"· tests with

sho~

0:

lODger

..

au.Uon than for the ~...r output.. - ID '.CUOD 1%, D&1Ziel and .tA. discussed only
•

continuous 60 lIZ and eSc with re.pect. to let. go

c:=r.ft~.

Dalziel'. study of 1m-

p\11s. shock, 11%, eSe.lt: with capacitor type dilchaZ1i•• rather than a continuous
. "'I

ua1D of

ac:=••
....

'ul.... '!'he electro convulsive therapy 1D ••

C~iOD IV

relate. to shocks

the beac! and are unlike the usual points of appllcat.ioft fo~ the 'la•• r.

.ec:t1oD V, tll.

a.L. •.....cUic

fence histozy is u•• ful exc.pt

fOJ:

1ft

the lower repeti-

"'e ground fault. circuit
•

!at;.rnp~.1' t ••u

li.~.4 1JI ••ctJ.on

VI have little d:lzec~ • •11c:atioft in thil

cu. . . t.hey apply to • cont.inuous 60 Hz

c1aZ'en~.

•

•
•

•

.

•

o
.

..

I

•

III

•

•

•

The heart fibrillation and lc~-90 c~rrcnt studies ~cre ~or ~O H: so thay ~~~t be
41

applied with great care fer the ~a5er type output.

The electrical shoek aecicer.t

history dealt primarily with sinqle e~pacitor discharge ty~e accidents so once
.9~ift

-

great care must be exercized in applying these data ~o ~.ser t~~e outputs.

Electzo·coftvulsive therapy applies shocks to the heAd, usually 60 Hz, so these
\

results have little application to Taser type output.

~h.

requirements for electric
•

fences and ground fault cireui~ interrupters mu.~ be us.d with great care because

of the type of electrical

outpu~

of the T••• r.

•

.

•

-

.

•

.

.

•

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•

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•

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oil

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•

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ELECTRIC n:::CES

L

.

References

••

1.

•

[

O.L. Bulletin of Research ~o. 14, "Electric shock as it
pertains to the electric fence", Six~h Printing, Oecen~er
1969 (Basically original report of Se?tember 1939) .

•

•

[

2.

O.L. 69, Standard for Safety, "Electric Fence Control:!.ers",
3rd Edition, May 1, 1972.

[

U.L. 69

•

The standard for the electric fence provides a good basis
for allowable, . safe, intentional electric shocks •

[
[

•

• 93

500 Q load for tests
(Lowest value for body resistance)

.98

·Off· period greater than 0.9 s for sinusoidal-type output

-

[

Greater than 0.75 s for peak discharge-type output
•

[[

(Since shocks are above. let-go level, this gives person
chanc~o ge~ ~e.
Continuous output is not
permitted.)

-

f100 Any single failure in the controller will not produce a
continuous current greater than 5 mAo

[
[
[
[

•

(This level should be below let-go

fl08 For peak discharge type output ·Off· period not less than
0.75 s •
•
·On· period not more than 0.2 s.
curve is provided for the maximum allowable output in mean
milliampere seconds versus time of the "on" period. This
actually specifies an allowable energy in the shock pulse.
A

o

,

•

1 2K

[-

2
W • i Kt

[

oW. (it)2

U
L·

c~rrQnt.)

W(J/s)

.

0

•

(1)

•

o

!t

J

(2)

J

(3)
•

The curve is for ·on· period time. from approximately 0.03 s
to 0.1 s. From 0.1 • to 0.2 s the allowable output is a constant 4 rnA-I. Using the value of T of 500 g and equation (3), ...-, .

;..1

o
o

•

.

•

-

~.

•

•

•

the following energies can be
•

.

0.03

0.04
0.06
0.08
0.10
0.20

•

•
•

W(J)

it(A-s)

t. (s)

,

calcula~ed:

2 x 10- 3

66 - 10-

3
2.5)(10-

78

10- 3
3
88 x 10-

3
3.25)(10-

3.7S )C 104 x 10- 3 .
3
4 x 10-

3

3

89

)C

)C

•

3
10-

3
-SO x 103
40 )C 10-

...

...

For sinusoidal ou~put
.On·- time les8 than O. 2 •
•Off- ttme not less than 0.9 s.
A str.igh~ line cU%ve of maximum allowable rms current versus
.on- time of~. shock is-viven for time of shocks from 0.03 s
to 0.2 s. This curve bas the equa~ion

'110

[

..

•

II

Irma • -350 t + 75
J

(4)

IDA

•

The allowable current from equation (4) i . compared to the
value ~hat could cause ventricular fibrillation derived
from the following equation.·
· ·
.
•
~

..-

-

1m ••

100

· -

InA

IE

•

iii'

..
II

t i . in a.coneS••

-0.025
t.

a.05
0.10
0.15
0.20

I rm8 • -350

I

+ 15 (mA)

.100 (mA)
rIU

65
57.5
40
22.5
5

It

w.• ,500 I~.JS t
3
52.8)(10-

m--~
...

82.'-10-

447
316

3

80 x 10- 3 "
3
37 x 10-

258

3
2S x 10-

223

•

,

•

Mach us.ful data bu~ • little 014. C
l1a~ed currents when a
119h~ bulb 1n series with 120V line and ~he fence are actually
hither than shown in ~. repor1: •• t.he cold r ••ls1:.ance of a
bulb 1. about 10' of ~. operating hot resistance.

[

..

•
•
•
•
•

•
•

(J)

...
,"

:

..

'.

•

•

..

ATTACHI·jEl:T

pn

2
.

.

The tollowlns
or the TASER.
1.
•
•
...

oil

.

~

~.--~

concern Dr. Eernstein's analysis

. .
Paracrapb 1 the reterence to "Appendix
-

2..

11 in
E" should read "Append1x C".

3.

One Pale 14, Paragraph 2,13 khz.represents a conservative frequency band and also simplifies the
mathematical anal~s1s.ot
the output waveform •
•

_.

On Page 2 and on Pa&.~O the current that will cause
cular fibrillation in adults 1. Irma • 1 0 (rna)

•

·

cou~ents

On Page 1 in Paragraph 2 the 1m~edance between ~a1rs
ot needle electrodes has been found to be on the order
or 200 ohms. J.C. Heesey, M.D. and F.S. Letcher,
M.D. or the Naval Me~1cal nesearch Inst1tute in their
report 'tr-l1n1mum Thresholds tor Ppys101og1cal Responses
~o Flow of Alternating Electric Current Through the
Human Body at Power-Transmission Frequencies" have
determined that the minimum resistance likely to be
encountered with small cuts and needle punctures
1s approximately 200 ohms. The place where the needle
electrodes contact the body does not seem to make
much ditference as has been verified by tests on
dOIS by Dr. Bernate1n.

..

.,

•

On ,ale

and in children 1s Irma • 100 (ma)

if .

The more conservative children's number has been used.
!his equation is a re~ult or Dr. Dalziel'. and Lee's
work with doss and animals and 1. explained 1n detail
in his report in IEEE Spectrum or February 1969
titled "Lethal Electric Currents".

5.

On Pale 20 it should be noted that the V-SOD I 2 rms t(J)
energy column relates to the Irma • -350t+7S(ma)
current column while the Irma • 100 (ma) current column
~

.

1. shown tor reterence to indicate the relative
allowable 60 hz current. Alao ple.s. note that the
t is mias1nl in current equation Irmr · -350 + 75(ma).
,..

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•••

WITH 7623 TECTRONIX SCOPE AND
P6015 TECTROnIX HI VOLTAGE PROBE:

.,

•

LOAD ON

WAVEFORM
•

NUMBER

A2~Jb

SIN

OUTP·UT

SIN

~;31~

2000

lA

2A

·2

500n

15

2B

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lC

2C

1&

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1D

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SCOPE TRACE NUMBER
TASER
TASER

15900n

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2E,2P

:1£
.
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1H

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SIN A331~

Pulses per second

+
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13.5 pps

•

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or

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QQVERNMENT

Memorandum

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· CONSUMe;:::a I=I=tOCUCi

SAFETY COMMISSION
WASHINGTON. O~ CA 202::7

.

•

•

TO

..

Albert F. Each, M.D., Director, OMD

••

raRU
...

1~~~

: Leo T. Duffy, M. D., Depu~y D.irector
Office of the Medical Director.:

10, 1976

~.

•

c=::=====~

"II

.....r:r; 'riSER '1'r-l, CP•

~he.Office of the Me4ical Director has reviewe~ the
.a~erial .~bmitted by your Office concerning the subject petition. A~thou9h this reply will concern itself

t

•

...

only with the ,medical ••pects of this sUbject, we
recognize at the·.tart that this product is manufactured as • -aangerous weapon-, ana should be so treated.
As such, it. effectiveness depends on the creation
o£ aome measure ~f injury in or~er to fulfill·its
intended purpos.. Therefore, it appears .that the role
of,this Office is mere conc.(ne~ with assessing the
-risk of ~nreaspnable in~urt:_rather than ~h~ "unrea~onable
risK of injury". This memor&Ddum will- not 'address
th. socia~ mora~ and-pnTlosophical issues which are
necessarily bound to be raised in the ~iscussion and
•
· consideration of the , use of this product.
From the electrical data, supplie~ as the design output,
ana our survey of the literature (references attached),
it is apparent that the stated available electrical
current (50,000 V/O.3 joule./10 PPS) is non-lethal
when the w••pon is used as directed on the -.verage,
healthy· .~ult. The current-related injury sustained
with the intended use 'of the TASER is relatea to the
neuromuscular system, and is exhibited .s an abnormal,
tetanic or sustained contraction of muscle groups which
has the effect of immobilizin; the recipient. This •
reaction is induced by the action of the-electric .
.current passing through the skin, anc! then following ·
nerve ?at~~ays by means of the nerve fibrils (cells)
"and thel- ...te1in sheaths, both of v·hleh .are excellent •
conductor 5. The cur r·en t i's then con t inued through
nerve endings (.ynapses) which art attached to muscle.
• ~b. transference of the charg- to the muscle cells
causes them to contract. This 1n~ury proclss, ordinarily,
is temporary an~ reversible when used as indic.te~
on the healthy human. Th. level of current is comparable
to tha~ of U.L. approved electric wire fences as far
•

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as the -freezing" action is concernec. However, a
major difference exists in that the e~ectric ~enc.
pulsed charge of approximately 4.0 mArnp has OFF .n~
O~ periods which would allow the a~~lity to "letgo·,
and get free from the fence. With the TASER the -letgo· is dependent on the user inter:upting the flow
of current by releasing the release bar.

•

•

With ex~osure to the stated amount of TASER current,
there is a wide margin of safety as related to causing
severe cardio-vascula: reactions. An alternating
current of 60-120 mAmperes, 120 Volt, 60 Hz can result
in ventr~cular fibrillation. This is an asynchronous,
uncoordinated rhythm of the heart beat which is incompatible with survival unless the normal rhythm is
restorea by means of a defibrillator device. The TASER
current of 0.3 joules (watts/second) is well below
the 10 to SO joule threshold above which ventricular
fibr illation can occur.. This safety mar'gin would be,
diminishec in a pe:son who has existing cardio-vascular
disease. For example, an el~erly person with arteriosclerotic
heart disease would be sUbj~c~ to the precipitation
of heart failure under the s~eS5 of convulsive seizures
associated with Electric Shock Tnerapy. The margin
of safety would also be reduced with
~_rolonged con;inuation
of TASER current.
·
--~~-- .

a

..

Injuries related to the impact of the barbed darts
causing puncture woun~s of the external s~rface of the
body would be relatively miner, except for impact on
the eye. The chance for initiation 'of events leading
to a total loss of vision in the .ff.ct.~ eye would ·
be extremely high should such contact occur. Electric
ener9Y applied in the vicinity cf the eye has alse
resulted in delaye~ cataract formation.

•

There is no evidence that adverse psychological, or
neurological, effects, stemming purely from the electric
current charge of • TASER, voul~ be induced.
r

•

[

Injur iel, :e5u1-'';'.a9 from fali. involv in; an incapacitated,
inert human body,. are speculative depending upon the
activity of the recipient at the time of impact, and
on contact with external hazard., such as the head

striking the sharp corner of • ta=le.

The

lik.lihoo~

of injuries, such as fracture., is increased in the
c••• of the aged or physically handicapped.

t~
\., I
.

•

.. In general, the severity of syste~ic e~~eets frcm the
passag e of electric current thro~;h :h. ~ody dep!nds
on ••veral factors. These are: 11 type of circuit,

.

:.. ..

.1

-

-

a

•

..

- J -

.
..

•

•

II

2) voltage, 3) value of the current., 4) du:aticn of
flo~, 5) resistance of specific tissue, 6) area of
cont~ct, and 7) pathways fol1o~ec through the bocy •
In .~dition, people with chronic cardio-vascular disease,
the elderly and children would be increasingly susceptible
to aaver~e effects. Therefore, this Office agrees
witb the conclusions stated by the man~facturet in
his summary of May 10, 1972, page 3, which reads
----the conclusions re.che~ as a result of these studies
and special tests is that the TASER is non-lethal at
~he design output to normally healthy people.
However,
it must b. ern~hasiz.d
that neither this feature nor
.

...

•
•

..

'

.

the non-injury or no harmful after-effect aspects can
ever be-guaranteed. ~here is no weapon, technique
or procedure for subduing, constraining or dispersing
that does not involve some risk of injury to healthy
persons or of death especially if the individual has
• heart ailment.-

~

..

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,

Refcrcnces
1)

' " ~ •.,
.
•.. ",
...'" a"al.,.Q4,;.w
.......
.....
•• _

r -I ~~s'"
\

.1....

_

"'."'"

~

..

"-0

.

- ...... ...

..

~,.-

, I

-. --.. ......
••

.---'--

Dabie1, C.r.; Electric• Shock i1a:arc,

•

. 4)

..... •

,-., . . . . ,

'-

.

'1-r
\"

...

·-_

-'"'

•

--,.

.....
'''''' .
.......
. .
,......
-.
~
1"""'s
..... •....... ..'" G..... _

...
·ce'l,....
-,

3)

[

,

... •• t">

~

Z)

[

.-

....

-._ ... .
'

::~ 5;cc:~_":1, Feb. 3972.

Dalziel, C.r.; Study of the t~zards of I~~se C~~~e:lt~.
American Inst. Electrical E.'lginee~s, \';1'''::, :~::: .

jr~~sa;:ic~s

c:

•

Electric Shock as it I'er~ainsto ~":e
Research. No. 14, D!cember 1969.

E:ec:~i:

........... -

[

S)

[

6)

Xouwenhoven, W.B.; Human Safety and El~c~T:c S~ock, Ele:~rical
Practices :,t>no~raph 112,. Instrunent SO,o:ic'::-' of ,';'~e~:ca, 196~.

[

7)

Turner, t1.S., J.I.D.; H\IIIan Responses, to Elec:':~ici ty, ,:.. Literature Revie.... ,
Chio State !.hiversity Research Founciation, 1972.

-.

-

8)

[,

..
-·~c·

• •••

I

,-

.

~'I"'~·;-

0.:

Sa:e~v
,

•

Farrell and Starr; Delayed Neurological Sequelae of :lectrical Injuries,
~.~, Vol. 13, 3, 83-97, October 19i1 .

•

Minimal Thresholds for Physioloiical Res?o~ses cf AC C~r~en': ~":rc~&:. ~,e
Bo9Y at Power·Transmission Frequencies, ~ava: ~~dical ~esear~, r~s~:':~~e,
Research Report No.1, Sept. 3; .n6S.
,

9)

[

~

,

,

[
[

•

•

Dalziel, C.F.; Reevaluation of Lethal :lec~~ic Curr~~ts, lEEF.Tra.'lsac':ic~s
Industry and General Applications IGA·4, No.5; Sept./O,t. lQ68, pp. 467-476.

11)

Sugimoto, T., SchUl, S.F., and lI'allacc, Idj.; racto~s Deterr.lining \'u:'"le~'
ability to Ventricular Fibrillation Induce: by 60-C?S Alternating Cur~en:.
'CIRC'JLATICN R!SEAACH, Vol. 21, No\'. 19~7, pp. 601·608.
.

12)

[

[
[

Bernstein, T.; Eilects o~lectri~ a.'ld.~l:l:1iJ:l~~"-:'"ldA'lir..a.ls,
Journal• of Forensic Sci~~ces, Vol. lB, ~~. 1. 1973.

10)

,

13)

Lee. W.R.; The Nature and ~Ia.~a~ement of Electric Shock, British Journal
of Anaesthesia, Vol. 36, 1964, pp. 572-580.

14)

Lee, W.R.; Death From Electric Shock, ?roccecings of The IEEE, Vol. 113.
Jan. 1966, pp. 144-148.
•

•

[

15)

[

16)

[

L

,

Hod~kin,

.-

B. C., Lang'o~orth)', 0., and L".:.1en.ioven. \I' .B.; Effect er. Breat.".ing
of an Electric Shock Applied to ~e Extremities. IEEE Transaction Po~er
Apparatus. and Syste~~, Transactions Pa,er 172 087-0. 1972 •

•

Peleslca. B.; Cardiac Arrh}'thmias Fo:lo...-in~ Condenscr Dischar,es ~d j";::~! .•,
Dcpc!'lde!'lce Upon StrClnl:th of CUTTe:'lt anc ?:,ase of CilJ'diac Cycle •. CI?C.-" ......
. RESE.ro\ROi, Vol. 13, July 1968, pp. 2:-32.
•

I
•

'-Ij

__

,. .
"

...

•

•

2
..

~f=Tcnces
•
J_

(Con~inued)
•

li)

W.B.; Er!ect of C~p~citor Discll~r,cs on the Heart, AlEE
Trans~ctions, 75, Part III, 1956, pp. 12-15•

18)

Geddes. L.A. and TackeT t W.A.;

.
·

~ou~cnhovcn,

En~incteTina

and r'hysiolo~ical Considerations
of Direct Capacitor-Discharae Ventricular Defibrillation, Medical :md

Piological Enaineering, Vol. '. 1971. pp. 185·199 .

•

.

19)

J)iVincen'ti. t-bncrief I PNi tt i Electrical InjuTies: A Kevil'" of 6S Cases,
Journal of Tra\l1\l. I Vol. g• No.6. 1969.

-.

•

20)

•

Pruit~;

..tencrief,

•

Electric Injury, PostlTaduate

~lec!icine.

Sept. 1970.
•

•

21)

Brown and MJri tz; ElectTic:al . Injuries. 196_3.

oil

•

.

~

•

22)

SkoOI. T.; Electrical Injuries. Journal of Tra1Jlll, Vol. 10, No. 10, 1970.

23)

Dalziel

24)

....,

1950.

Ina Mansfield;

Effeet- of rrequency on Perception Currents, AlEE,

'"

nine and Friauf; Electric Shock, Its causes and Prevention, Bureau of
S~ips.

25)

.......

.

-

Bernstein. T.; Direct Current Shpc:,is, Oc:t. 2.4, 1975. (J)ersonal conmunica'tion)

--

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. . . . 111

__
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_----~

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•

 

 

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