CERAMIC VARISTORS TNRTECHNICAL NOTE

TM

1. WHAT IS A VARISTOR?
A varistor has the volt-ampere characteristics in which current suddenly starts to flow through the device at a certain voltage, as
shown in Figure 1.
The varistors are used to protect semiconductor devices in electronic and electric circuits from overvoltage. As shown in Figure 2, avaristor is inserted in parallel with a circuit to be protected. When an impulse is applied to the circuit, pulse current ls, which isdetermined by pulse voltage Vs and pulse impedance Zs, flows to limit the pulse voltage to the varistor limit voltage Vclamp.
The relation can be expressed by the equations as follows:
Vs = Is × Zs + Vclamp(1)
Vclamp = Vs - Is × Zs
(2)
The pulse current ls is easily obtained by the following equation because of Vs >> Vclamp.
Is ≒

Vs
Zs

(3)

Thus, the circuit can be protected from being damaged by pulse voltages as long as it has withstand voltage larger than the
maximum limit voltage.
Owing to the characteristic, the varistors are extremely effective as protecting devices of electronic and electric equipment byabsorption of abnormal voltages and lightening pulses.

Pulse impedance

Pulse
sourcePowersupplyCircuitto beprotected

Varistor

Pulse current
20

Current (mA)

10
-300

-200

-100

100

200

300

Voltage (V)
-10
-20

(V)
10000

(V)
10000

8000

8000

6000

6000

4000

4000

2000

2000

0

20

60 80 100 (µs)

Pulse voltage
waveform

0

20 40 60 80 100 (µs)

Pulse absorption
characteristic of Varistor

Fig. 2 Pulse absorption by varistor

Fig. 1 Volt-ampere characteristics of varistor

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2. SAMPLE USED AND NOTES ON Varistor
This chapter describes general sample uses and notes on use of Varistors. Take these conditions into consideration when you selectVaristors of appropriate ratings.

2-1 PROTECTION FROM POWER PULSE(1)Examples of wiring

Line to line protection

Line to line and line to ground protection

DC or single-phase AC

DC or single-phase AC
Circuitto beprotected

Varistor
Circuitto beprotected

Varistor

Varistor2

Three-phase AC

Three-phase AC
Varistor
Varistor

Circuitto beprotected

Circuitto beprotected

Varistor4(2)Examples of rating selections

Varistor used for line to line
Power Voltage
AC100V
AC200V
DC12V
DC24V

Varistor used for line to groundType
TND □□ V-221K
TND □□ V-241K
TND □□ V-271K*
TND □□ V-391K
TND □□ V-431K
TND □□ V-471K*
TND □□ V-220K
TND □□ V-270K
TND □□ V-330K
TND □□ V-390K
TND □□ V-470K

Varistor

Power Voltage

Varistor2

AC100V
AC200V

Varistor4

AC200VType
TND □□ V-431K
TND □□ V-471K
TND □□ V-911K≦**
TND □□ V-182K ***TND □□ V-431K
TND □□ V-471K
TND □□ V-911K≦**
TND □□ V-182K ***Notes:
1)In an insulation resistance test (500V mega test) of aunit, it may incorrectly judged to be bad due to its leakcurrent from the Varistor mounted on the unit. Test theunit with the Varistor removed after obtaining approvalof the unit user on removing the Varistor. Or use a
Varistor with mark ** for the test unit.
2)In a withstand voltage test (1000 VAC test) of a unit, it
may incorrectly judged to be bad due to its leakage
current from the Varistor mounted on the unit. Test theunit with the Varistor removed after obtaining approvalof the unit user on removing the Varistor. Or use a
Varistor with mark *** for the test unit.
3)Use a Varistor of 200 VAC type between the 100 VAC
power line to ground to prevent the power supply frombeing damaged by overvoltage such as ground-fault.

Notes:
1)If a Varistor is used at power voltage other than theexamples above, never make the power voltage
increase over the maximum allowable voltage.
2)For individual wiring or capacitive load, the power
voltage is temporarily increased by resonance at
switch on or off. Thus, use a Varistor of the type withmark * for the power of 100 VAC or 200 VAC.

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2-2 PROTECTION OF SEMICONDUCTORS AND ICs FROM INDUCTIVE ON/OFF PULSESAND ERASE OF CONTACT SPARKS(1)Examples of wiring

Switching surge protection

Semiconductor protection

Erasing contact sparks

M(2)Examples of rating selections

Examples of general selections

Power Voltage
DC 12VDC 24V
DC100VType
TND □□ V-220K
TND □□ V-390K
TND □□ V-151K

AC100VTND □□ V-221K
TND □□ V-241K
TND □□ V-271K

Notes:
1)If a Varistor is used at power voltage other than the examples to the left, nevermake the power voltage increase over the maximum allowable voltage.
2)For other than a complete DC voltage, never make the maximum peakvoltage increase over the maximum allowable voltage.
3)Take the pulse energy generated in load into account sufficiently to define
the maximum peak current, maximum energy, and rated wattage.

(3)Notes on use of Varistor
1. Be careful of the notes described in Section 2-1 �PROTECTION FROM POWER PULSE.�
2. Select a proper Varistor satisfying the desired relationship between the number of pulse applications and the Varistor rating,referring to the reduction curve of pulse life time ratings.
3. Select a Varistor having rated wattage larger than averaged pulse wattage to make the Varistor absorb high-frequent pulses.

2-3 REDUCING PULSES ON SIGNAL TRANSMISSION LINES(1)Examples of wiring
SIG.1
SIG.2
SIG.3

Transmission
equipment

SIG.4

COM.

(2)Examples of rating selections
Signal Carrier Voltage
DC 12V max.

DC 24V

Examples of general selections
Notes:
1)Any Varistor includes electrostatic capacitor listed in the rating table. Take
TND □□ V-150K
special note when a Varistor is applied to high-frequency signal.
TND □□ V-220K
2)When signal of higher voltage than that of normal signals (such as bell
TND □□ V-820K≦
signal) is superimposed on normal signals, select an appropriate Varistor
available for the higher voltage.
TND □□ V-390K
3)Use a Varistor with a type of varistor voltage 82V or higher if signal is too
TND □□ V-820K≦
low to be attenuated.
Type

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2-4 Examples of selections in fields
Use

Location
IndoorCommercial
OutdoorTND07V- □□□ K
TND10V- □□□ K
TND12V- □□□ K
TND14V- □□□ K

Indoor

TND07V- □□□ K
TND10V- □□□ K
TND12V- □□□ K
TND14V- □□□ K

OutdoorTND07V- □□□ K
TND10V- □□□ K
TND12V- □□□ K
TND14V- □□□ K

Indoororoutdoor

TND14V- □□□ K
TND20V- □□□ K

Communication,
Measurement,
Control

Industry,
Power

Example of general selections
Type
Notes
TND05V- □□□ K1)Each number in the range between 5 to 20 specifies the diamTND07V- □□□ K
eter of a Varistor. The larger the diameter is the greater the
TND10V- □□□ K
maximum peak current of the Varistor is. Select a Varistor of the
TND12V- □□□ K
type covering the expected peak current.

2)Pay sufficient attention to the conditions peculiar to the unit onwhich the selected Varistor is mounted as well as normal selection examples.

2-5 Notes on use

Take the notes for reduction of power pulses into account as well as those explained below.
1. Take the action shown in the figure below because the Varistor may be short-circuited or broken when it absorbs a pulse
exceeding its rating.
A

Unit to beprotected

Power line
BC1)Mount the Varistor closer to the circuit than the overcurrent protector such as a breaker or fuse to disconnect the Varistor
from the power supply immediately at short circuit of the Varistor.
2)Mount the overcurrent protector at location B if it cannot be mounted at location A.
3)Selection examples of ratings of fuses mounted at location A or B are listed below:
Type (TND-)

05V- □□□ K

07V- □□□ K

Fuse rating

3A max.

5A max.

09V- □□□ K
10V- □□□ K
12V- □□□ K
7A max.

14V- □□□ K
20V- □□□ K
10A max.

4)Use a leak breaker or at position A or mount a temperature fuse connected thermally to the Varistor at position C if the
Varistor inserted between the power line and the earth is grounded to the unit earth. It is also effective to use a Varistor of
the GF series which includes a thermal fuse.
2. Check that the Varistor is used within the range of the rating operating temperature if it is exposed to direct sunlight or placed neara heating unit.
3. Make wiring of the Varistor as short as possible. With long wiring, large voltage drop occurring at a rapid rising pulse on the L
component of the wiring causes the Varistor not to be effective enough for surge absorption.

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3. SELECTION OF Varistor RATING
3-1 RATING SELECTION PROCEDURE①①Make clear pulse sources and invasion paths including outer lightening, inner lightening (on/off lightening), line to line portion, line to ground portion, powerline, and signal line.
②See the Sample uses and notes on Varistor
described earlier for the connections of Varistors.
③Set the varistor voltage so that the circuit voltage
may not exceed the maximum allowable voltage.
Take fully care of the applied voltage in insulating
resistance or withstand voltage test if the Varistor isinserted between a line to ground.
④The peak pulse current is almost equal to the value
obtained by dividing the expected pulse voltage by
the pulse impedance.
⑤Select a Varistor with device diameter for the
maximum peak current larger than the peak pulse
current if the expected number of pulses are notmore than 2.
⑥if many impulses are expected, select a Varistor with
device diameter for pulse life time longer than therequested life time, referring to the figure of pulse life
time ratings.
⑦Select a Varistor with device diameter for rated
wattages larger than the averaged pulse wattage if
pulses are applied continuously to the Varistor at ahigh rate.
⑧Take care of the maximum energy as well if impulses
are expected to have high energy.
⑨Select the varistor voltage and diameter of Varistor
so that the withstand voltage of the unit to beprotected exceeds the maximum clamping voltage. If
no Varistor can satisfy the requested characteristics,
it may be necessary to make the withstand voltage ofthe unit higher.
⑩Contact us when you use a high frequency circuit.
The capacitance of the Varistor may attenuate highfrequency signals and the Varistor may be heated by
the loss.
⑪See the maximum leakage current known from thevolt-ampere characteristic curve.
⑫Make wiring as short as possible. With long wiring,large voltage drop occurring at a rapid rising pulseon the L component of the wiring and its magnetic
joint with other wiring cause the Varistor not to beeffective enough for surge absorption.
⑬Connect a fuse before the Varistor. See 2-5 forselection of a fuse.
⑭Take note that the temperature around the Varistor
does not become larger than the maximum operating temperature.
⑮Perform installation test as much as possible toconfirm the performance of the Varistor.
⑯The action for absorbing pulses by Varistor is now
completed.

Confirmation of pulse
source and invasion path
YES②

Determination of Varistor
connection method
YES③

Set of varistor voltage
YES④

Set of pulse current
waveform
YES⑤

Is the maximum peak currentof Varistor enough?

NO

YES

⑥

Does Varistor has sufficientpulse life time?

NO

YES

⑦

Is the rated wattage of Varistor
enough?

NO

Selection ofVaristor withlarger device
diameterYES⑧

Is the maximum energy ofVaristor enough?

⑨

Is the condition thatclamping voltage is lessthan withstand voltage ofunit satisfied?

⑩

Does excess capacitance
and/or loss occur?

NO

YES

YES
NO

YES

⑪

Does large leakage current
appear?

NO

Selection ofVaristor withsmaller device
diameter andhigher varistor
voltage

YES⑫

Cheak of wiring
YES⑬

Is sufficient measure taken
for overload?

NO

Installation ofproper fuse
and/or leakbreaker

YES⑭

Does environmental
conditions enter into rangesof specifications?

⑮

Does Varistor succeed ininstallation test?

⑯

Completion of pulse
measure

YES
NO

YES

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3-2 EXAMPLES OF Varistor SELECTION

3-2-1 ACTION FOR EXTERNAL LIGHTENING PULSES OF POWER SUPPLY OF CONTROL UNIT
(1)Target circuit

Pulse AC100V

Varistor

Rectificationand control
circuits

Conditions
1)Withstand voltage Vt: 600V
2)Pulse impedance Zs: 50ohm
3)Pulse voltage Vs: 12kV at duty cycle of 1.2/50µsec
4)Number of pulses: 100 = 10times × 10years
5)Pulse interval: 2 minutes or more

(2)Selection of Varistor based on rating selection procedure
1. Confirmation of pulse source and invasion path: Circuit between external lightening pulse and power line. (The unit is not
grounded.)
2. Determination of Varistor connection method: Between power lines. (AC power input side of unit to be protected.)
3. Set of varistor voltage
Select the Varistor of 270V type based on the above sample use, because it is inserted between the 100 VAC power lines. Selecta proper type of a Varistor if the relationship between the withstand and clamping voltages of the unit to be protected does notsatisfy the condition described in item 9.
4. Set of pulse current waveforma)Pulse current peak value (Ip)
Ip =Vs
12,000== 240[A]Zs50b)Duration of wave tail of pulse current
The duration of wave tail of pulse current can be shorter than that of pulse voltage. However, set the duration of wave tail ofpulse current T to 40µs for safety. (In actual, it is about 25µs if the pulse voltage wave has the duty cycle of 1.2/50µs.
5. Is the maximum peak current of Varistor enough?
Because the maximum peak current is 240A, it is often considered that a Varistor of 5V type with the maximum peak current of
250A (secured for two pulses) can be available. However, the duration of wave tail of pulse current is not 20µs for a total of 100
pulses. Thus it is necessary to check the pulse life time of the Varistor.
6. Does Varistor have sufficient pulse life time?
The conditions include Ip = 240A, T = 40µA, total number of pulses = 100, and pulse interval = 2 minutes or more. Collate thesefour conditions with the pulse life ratings of the Varistor. (Refer to the manual of CAT. No. 1006 for the pulse life time ratings.)
Varistor Type
5V
7V

Number of pulses
2 to 1010 to 10010V

100 to 1000

14V

1000 to 10000

Depending on the above specification, a Varistor of the 10V type can be selected. Thus the Varistor of type TND10V-271K isdetermined as a candidate from the results above together with the result described in Item 3.
7. Is rated wattage of Varistor enough?
The rated wattage of the Varistor should not particularly be taken into account because the pulses are supplied to the unit at a
low frequency.
8. Is the maximum energy of Varistor enough?
The maximum energy of the Varistor should not be taken into account because lightening pulses of short duration of wave tail isonly applied to the unit.
9. Is the condition that clamping voltage is less than withstand voltage of unit satisfied?
The maximum clamping voltage of TND10V-271K is defined as V25A = 455Vmax in the rating table. However, since the maximum
current flowing through the circuit is 240A, the voltage at 240A should be read from the Varistor volt-ampere characteristics tocompare it with the unit withstand voltage of 600V. The relationship is satisfied as follows: V240A = 510V < 600V
(See the manual CAT. NO. 1006 for the Varistor volt-ampere characteristics.)
10. Does excess capacitance and/or loss occur?
As the power line of commercial frequency 50 to 60 Hz is low frequency, it does not cause severe problems.
11. Does large leakage current appear?
As the 100 VAC power line produces only a small leakage current of several µA, it does not cause severe problems.
12. Check of wiring
Note that the wiring to the Varistor is not be electrostatically and magnetically coupled with the rectification circuit and control
circuit lines. Make the wiring as short as possible to minimize the stray inductance.
13. Is sufficient measure taken for overload?
Attach a fuse of about 5A before the Varistor for occurrence of overvoltage. (See 2-5.)
14. Do environmental conditions enter into ranges of specifications?
Check operating temperature range of the unit unless it is used near heaters such as coils.
15. Does Varistor succeed in installation test?
Perform the test with TND10V-271K connected to confirm the performance of the unit.
16. Completion of pulse measure
After insertion of TND10V-271K to the unit as shown in the figure, the action required for absorbing pulses is now completed.

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CERAMIC VARISTORS TNR
3-2-2 ACTION FOR ON-OFF PULSE FROM RELAY(1)Target circuit
DC110V

Varistor

L

TM

TECHNICAL NOTE

Conditions
1)Coil rating: I = 0.25 A, L = 1H2)Relay operation: 2 times per sec, 8 hours per day, and 6 days per week3)Life: 5 years4)Number of pulses: 2 × 3600 × 8 × 313 × 5 = 0.9 × 108
5)Desired suppress voltage: up to 250 V(2)Selection of Varistor based on rating selection procedure
1. Confirmation of pulse source and invasion path: Wiring between on/off relay line and power line.
2. Determination of Varistor connection method: Between power line (in parallel with coil).
3. Set of varistor voltage
A Varistor will be inserted between the 110 VDC power lines. Because the application is not defined as a typical example, the varistor
voltage must be determined from the relationship between the circuit voltage and the maximum allowable voltage. Select the Varistor oftype 151K (150V) with the maximum allowable voltage of 121V or more, assuming voltage fluctuation of + 10%.
4. Set of pulse current waveforma)Pulse peak current (Ip): 0.25A same as load current.
b)Duration of wave tail of pulse current
The duration of wave tail of pulse current can be calculated from the following equation assuming the pulse current wave to be a squarewave.
E = 1/2L Ip2 = 0.5 × 1 × 0.25 × 0.25 = 0.031[J]T=

0.031 × 1000
E=
= 0.56[ms]0.25 × 220
Ip・Vp

where Vp: estimated clamping voltage of Varistor of type 151K at 0.25A read from the Varistor volt-ampere characteristics.
5. Is the maximum peak current of Varistor enough?
Check the pulse life time of the Varistor because pulses occur at a high frequency.
6. Does Varistor have sufficient pulse life time?
The conditions include Ip = 0.25A, T = 0.56msec, number of applied pulses = 0.9 ×108, and applied pulse interval = 0.5 sec. Since theapplied pulse interval is shorter than the specification of 10 sec, the equivalent current and the equivalent number of applied pulses
should be found with the equivalent interval set to 10 sec.
Equivalent current = 0.25 ×

10= 5[A]
0.5

Equivalent number of
0.5
applied pulses = 0.9 × 108 ×= 4.5×106

10

In addition, the duration of wave tail of the pulse current T is 0.56msec = 560µsec as known from the result of ltem 4. Collate these
conditions with the pulse life time rating of the Varistor.
Varistor type

Number of pulses

7V

105 to 106 < 4.5 × 106

10V> 4.5 × 106

Depending on the above specification, a Varistor of the 10V type can be selected. Thus, the Varistor of type TND10V-151K is determined
as a candidate from the results above together with the result described in Item 3.
7. Is rated wattage of Varistor enough?
The averaged wattage Ps[W] absorbed by the
Varistor is, Ps = E fs = 0.031 × 2 = 0.062[W]where fs is the repeated pulse frequency [times per sec]. From the viewpoint of the absorbing wattage, a Varistor of 5V type (0.1W) may beavailable. However, a Varistor of 10V type (0.4W) is better if the pulse life time ratings of the Varistor in Item 6 is also taken into account.
8. Is the maximum energy of Varistor enough?
This is already considered in the pulse life time because many pulses are applied to the Varistor (see Item 6).
9. Is the condition that clamping voltage is less than withstand voltage of unit satisfied?
The maximum clamping voltage of TND10V-151K was assumed to be about 220V in Item 4. By checking it with the Varistor volt-ampere
characteristics, we find V0.25A = 210V < 250V. Thus this requested characteristic is satisfied.
10. Does excess capacitance and/or loss occur?
As the DC power line does not cause severe problems.
11. Does large leakage current appear?
As the 110 VDC power line produces only a small leakage current of several µA, it does not cause severe problems.
12. Check of wiring
Insert the Varistor near the coil as much as possible to reduce induction to other components.
13. Is sufficient measure taken for overload?
Attach a fuse of 3A to 5A before the Varistor for occurrence of overvoltage.
14. Do. environmental conditions enter into ranges of specifications?
Check operating temperature range of the unit and temperature near the coils.
15. Does Varistor succeed in installation test?
Perform the test with TND10V-151K connected to confirm the performance of the unit.
16. Completion of pulse measure
After insertion of TND10V-151K to the unit as shown in the figure, the action required for absorbing pulses is now completed.
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4. LOAD REDUCTION CURVE OF Varistor FOR TEMPERATURE

V, GF series
100
90

SV, H series
80

Load (%)

70
60
50
40
30
20
10
0
-40

20

40

60

80

100

120

140

160

Ambient temperature (℃)
Fig. 3 Load reduction curve

The load includes the rated wattage, maximum allowable voltage, maximum peak current (SV series : Values of 2 times), maximum
energy. For example, when TND10V-221K is used at 95�, the load is found to be 75% from the load reduction curve above. Thus,
the parameters can be calculated as follows.

1. Rated wattages

0.4W × 0.75 = 0.3W

2. Maximum allowable voltage

AC : 140V × 0.75 = 105V
DC : 180V × 0.75 = 135V

3. Maximum peak current

2500A × 0.75 = 1875A

4. Maximum energy

27.5J × 0.75 = 20.63J

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5. DETERIORATION OF Varistor
5-1 DETERIORATION OF Varistor(1)In case where no pulses are applied to Varistor
As known from the relationship between mean life of Varistor and ambient temperature shown in the figure below, a Varistor canhave the mean life of longer than 100 years if it is used at ambient temperature and circuit voltage within their maximum ratings.
Accordingly it can be said that the Varistor has hardly been deteriorated.

1

1

Mean life = 5960 × 109677( T+273 - 406 ) (h)108At maxmum allowable voltage
At 80% of maximum allowable voltage

Mean life (h)107(Year)
100

106
105

10

104

Defective condition: VCmA > ± 10%103

180 170 160 150 140 130 120 110 100 90
80
70
125
85
Ambient temperature (�)

60

50

40

30 25 20

Fig. 4 Relationship between mean life Varistor and ambient temperature(2)In case where pulses are applied to Varistor
Being a pulse absorption component, the Varistor is deteriorated if it is subject to pulses exceeding its rating.
1. With lightening pulses applied to a Varistor, the waveform, energy, and frequency cannot be defined. Thus the period taken
until the Varistor is deteriorated cannot also be determined.
2. With on/off pulses applied to a Varistor, the waveform, energy, and frequency can be measured or estimated. Thus the period
taken until the Varistor can almost be estimated from the pulse life time ratings.
However, because a Varistor with the rating suited to the requested pulse life time ratings is normally selected, the Varistor will
hardly be deteriorated within the life of equipment including the Varistor.

5-2 HOW TO CHECK DETERIORATION OF Varistor AND FREQUENCY OF THE CHECKING(1)Deterioration of Varistor
The Varistor is deteriorated by overvoltage application caused by overpulses and fluctuation of power voltage.
Adsorption of Excess Energy
Short Circut→→

Increase in Leakage Current→

Heat Generation→

Thermal Runaway→

Destruction (The Varistor may be opened depending on conditions)(2)How to check deterioration of Varistor
As described in (1) of Section 5-2, the deterioration of a Varistor is known by increase in leakage current. Accordingly, how a
Varistor is deteriorated can be measured by the leakage current.
The initial value of the leakage current of a Varistor (or leakage current occurring when the DC voltage half of the nominal varistor
voltage is applied to the Varistor) is about 1µA though the value varies depending on the rating of the Varistor. The leakage
current of 10µA is a sign that deterioration begins in the Varistor, so the Varistor should be replaced with a new one.
However, the leakage current of 10µA causes the Varistor to generate only the minimum heat, which will not lead the thermal
runaway immediately. The Varistor has a shorter pulse life than that in the initial state.

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6. PULSE PESPONSE CHARACTERISTICS OF Varistor
The Varistor itself has a response time for a pulse as extremely short as 1 nsec. However, it is difficult to measure the time becauseof a large influence of the inductance of lead wire.
In actual use, the clamping voltage is increased a little with a fast rising pulse even at the same current because of influence of theinductance of lead wire. Figure 5 shows the ratio of clamping voltages at faster pulse rise times to the clamping voltage at applicationof standard pulse current waveform of 8/20µs, which is called overshoot ratio. The figure is an example when pulse current having
rising time of 0.5µs to 8µs and constant peak current of 10A are applied to TND14V-271K. In the figure, the overshoot of about 10%
appears at the rising time of 0.5µs.
In actual use of Varistor, the rising of pulse voltage is limited by inductance and capacitance on the way to transmit in line. The risetime is almost not less than 1µs.
The wiring should be as short as possible because longer wiring make the overshoot higher.
Figures 6 and 7 show pulse absorption characteristics of a Varistor with the wiring lengths of 5mm and 25cm respectively, as
extreme examples. In these examples, the clamping voltage with wiring length of 25cm is about 1250V, which is about two times anda half of the clamping voltage of about 500V with wiring length of 5mm.

140

TND14V-271K

130

Overshoot ratio (%)

Current: 10A
120

110

100

100%
@
8µs

90

0.2

0.4 0.50.6

0.8 1

2

4

5 6

8

10

Pulse rise time (µs)
Fig. 5 Relationship between pulse rise time and overshoot ratio

500 V/DIV
0.2µs/DIVTND14V-271K

500 V/DIV
0.2µs/DIVTND14V-271K

Raw pulse wave

Raw pulse wave

Wave in connectionof Varistor

Wave in connectionof Varistor

Fig. 6 Pulse absorption characteristic ofVaristor (wiring length of 5mm)

Fig. 7 Pulse absorption characteristic ofVaristor (wiring length of 25cm)

Product specifications in this catalog are subject to change without notice.Request our product specifications before purchase and/or use. Please use our products based on the information contained in this catalog and product specifications.

107

CAT. No. E1006G 2024

METAL OXIDE VARISTORS TNRTM(1)Power Source Curcuit

APPLICATION EXAMPLES(2)Micro Computer Equipment
SwicthAC110V

AC110VTND14V-271K

TND14V-271K
Motor Relay
Solenoido
Power(3)Vending Machine(4)Leakage Current Detector
AC220VTND14V-271K

AC110VU

Vending Machine
Control Circuit

V
W

5

5

TND14V-471K

TND14V-471K(6)Control of 20kW DC Motor(5)Maganetic Brake

Gate Circuit

AC220VTND14V-471K

L
AC220VTND14V-471K

TND20V-471K TND20V-471K

U

TND20V-471K

V

M

W
TND20V-471K
TND20V-471K TND20V-471K(7)TelephoneT

TND20V-471K

R

TND10V-471K

Product specifications in this catalog are subject to change without notice.Request our product specifications before purchase and/or use. Please use our products based on the information contained in this catalog and product specifications.

108CAT. No. E1006G 2024