PTC Thermistor (PPOSISTOR(R)) - Jameco Electronics APP Catalog.pdf · for EU RoHS Compliant • All...

Cat.No.R16E-4

PTC Thermistor(POSISTOR®)

Application Manual

MurataManufacturing Co., Ltd.

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CONTENTS

1 Characteristics of POSISTOR®

2 The basic design data

3 Structure of POSISTOR®

POSISTOR® Application and Variety ListYYYYY02

Characteristics of POSISTOR®Y YYYYYYYYYYYYYY03

1. Introduction ..................................................................................03

2. Characteristics of POSISTOR®....................................................03

The basic design dataY YYYYYYYYYYYYYYYYYYYYYYY04

1. Resistance - temperature characteristics..................................04

2. Voltage - current characteristics (Static characteristics).........05

3. Current - time characteristics (Dynamic characteristics) ........06

Structure of POSISTOR®YYYYYYYYYYYYYYYYYYYYY07

Practical applications of POSISTOR®Y YYYYYYY08

1. Heating (Automatic temperature adjustment heater) ...............08

2. For temperature sensor and temperature compensation ........09

3. For current control..................................................................... 011

TermsY YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY012

!Strict observance ........................................................................012

!Notice ...........................................................................................012

1

2

3

4

4 Practical applications of POSISTOR®5

5 Terms

POSISTOR®.and."POSISTOR".in.this.manual.are.the.trademarks.of.Murata.Manufacturing.Co.,.Ltd.



2



POSISTOR® Application and Variety List

Application Target device

Over current Protection Overheat Sensing Temp com-pensation Heater Motor

starter

Chip typePRG

Lead typePTGL

Chip typePRF

Lead typePTFLPTFM

Lead typePTRL

Contact typePTWSBPTWTA

Hot air typePTWH

Case typePTH6MPTH7MPTHTM

AV equipment

Plasma TV K K K K K

LCD TV K K K K

Projection TV K K K K

CATV K

STB K

Video camera K K

Digital camera K K

DVD recorder K K K

VTR K K K

Audio K K K K

Electric keyboard, Electronic music instrument K K K K

Digital mobile audio K K

MD/CD player K K

TV game K K K

Portable game K K

Information equipment

Laptop K K

Desktop computer K K

Server K K K K

Printer K K K K

Scanner K K

LCD display K K K K

USB access device K

HDD K

CD/DVD-ROM/RAM K K

Copy machine K K K K

Electronic dictionary/databook K K

Electronic blackboard K K K K

Communica-tions equip-ment

Electronic automatic exchange K

Transmission equipment K

PBX K

Cordless telephone K

Fax machine K K K K

Modem K

Cellular phone K K

Headset K

Cellular phone base station K K K K

Intercom K K

Car electronics

Engine control ECU K K

Drive control ECU K K

Air-bag K

Anticollision radar K

ABS/ESC K K

Instrument/display panel, Meter K

Rechargeable battery for EV/HEV K K

Car air conditioner K K

Heater, HVAC K

HID/LED headlight, AFS K K K

LED tail light K K K

LED interior light K K

Retractable electric mirror K

Door lock, trunk opener K

Power seat K

Shock absorber K

VICS, ETC K

Burglar alarm K K

Car navigation K K K

Car audio K K K K

Home electronicsHousehold equipment

Refrigerator K K K K

Microwave, Oven K K K

Electric rice-cooker K K K

IH cooking device K K

Air conditioner K K K K K

Fan heater K K

Cleaner K K

Bath dryer K

Clothes washer, cloth dryer K K

Futon dryer K

Hot-air heater K

Electric pot K

Ventilator K

hot-water pot K K K

Humidifying device K

Inhaler K

Illumination device K K K K

Massage chair, healthcare equipment K K K K K

Curling iron K

Potable compact iron K

Hot water spray toilet seat K K K K

Electric power tool K K K K

Electric mosquito extermination, fragrance device K

Power supplySwitching supply K K K K

Inverter power K K K K

AC adapter, battery charger K K K

3



2. Characteristics of the POSISTOR®

Basically,. the.POSISTOR. increases. its. resistance.value,.when. its. temperature. rises.. From. this. phenomenon,.

1

1 Characteristics of POSISTOR®

Resistance - temperature characteristics

(time independent)

Voltage - current characteristics(Static Characteristic,

time independent)

Current - time characteristics (Dynamic characteristic,

time dependent)

Basic characteristics

Resistance at 25degC

Ambient temperature (Ta)

Features

Temperature change can be detected because the resistance of POSISTOR is changed by ambient temperature.

This characteristic shows the relation between the applied voltage and stable current, when the Thermistor internal self-heating equals the heat dissipated by the Thermistor to the outside (state of equilibrium). Each above chart is composed of constant resistance area, maximum current point and constant power area.

This characteristic shows the relation between current and time as equilibrium is achieved between internal self-heating and heat dissipation under the applied voltage.

Functions & applications

1. Temperature sensing, temperature compensation

2. Overheat protection of electric equipment, electric devices, Heater devices, Power supplies. Power IC/FET

1. Current control, over current protection

2. Constant temperature heater3. Detector element using change of

heat dissipation factor4. Constant voltage and constant

current equipment

1. Motor starter element (Motor starter relay)2. Timer delay element

!Table 1 Characteristics of POSISTOR

Temperature (°C)

104

103

102

10

1

0 50 100 150 200

Res

ista

nce

Valu

e (Ω

)

log V Voltage

log

I C

urre

nt

Consta

nt Res

istan

ce Constant Power

Time (sec.)10 15 20 25

Cur

rent

(A)

Temperature (°C)

log R(Ω)

Resistance Value up

log V

Resistance Value up

log I

Time (sec.)

Resistance Value up

Cur

rent

(A)

Temperature (°C)

log R(Ω)

log I

log V

Ta up

Ta up

Time (sec.)

Cur

rent

(A)

Barium.titanate.(BaTiO3).is.a.ferroelectric.substance.that.was.first.identified.in.1944..Its.resistivity.at.room.temperature.becomes.an.n-type.controlled-valency.semiconductor.with.1-106ohm.·.cm,.if.a.slight.amount.of.rare.earth.elements.are.added.to.Barium.titanate..It.was.first.made.in.1951..Murata.was.extremely.interested.in.this.semiconductor.and.successfully.starting.the.first.commercial.production.of.the.POSISTOR.in.1961.

Since.then,.it.has.been.applied.to.several.applications.under.the.name.of.POSISTOR.

POSISTOR.is.Positive.Temperature.Coefficient.Thermistor.(PTC.Thermistor)..Normally.when.the.temperature.increases,.the.resistance.of.conventional.Thermistor.decreases..But,.the.resistance.of.PTC.Thermistor.rises.sharply.when.its.temperature.exceeds.a.specific.temperature.

1. Introduction

three. characteristics. can.be.made,.which.are.described.below.

4



2

1. Resistance - temperature characteristics

The.POSISTOR®.has.resistance.-.temperature.characteristics.that.cause.its.resistance.to.exponentially.increase.when.the.part’s.temperature.exceeds.its.Curie-point.(Cp),.the.critical.temperature.where.the.resistance.value.increases.dramatically..Typically.above.the.Cp,.the.resistance.of.POSISTOR.increase.at.rate.of.15%.to.60%.per.degC..There.are.many.kinds.of.Cp.available.(from.40degC.to.280degC,.as.shown.in.Fig..1,.table.2.and.table.3).which.allows.for.the.easy.selection.of.a.suitable.Cp.for.each.application.Some.special.POSISTOR,.products.with.a.Cp.below.room.temperature,.exhibit.a.more.linear.rate.of.resistance.increase.of.5%.per.degC,.above.its.Cp.If.a.resistor.is.connected.with.the.POSISTOR.in.series.or.parallel,.the.resistance.-.temperature.characteristics.


!Table 2 Resistance - temperature characteristics

Clas-sifi-

cation

Temper-ature

charac-teristics

Description of characteristics Applications

(ⅰ) T

Exhibits a generally uniform positive resistance temperature characteristics (about 5%/degC) within the temperature range of room temperature to 60degC

Temp. compensation, Temp. sensing

(ⅱ) BH-AR

Exhibits an almost linear resistance increase between room temp and the Cp, with an abrupt resistance increase above the Cp. Cp is available in a range from 40degC to 120degC, selected by temperature characteristics

Temp. sensing, Overheat sensing, Motor starting, Heaters

(ⅲ) AR-ADExhibits a less than linear resistance increase from room temperature to the Cp, with an abrupt resistance rise over the Cp.

Temp. sensing, Overheat sensing, Over current protection, Motor starting, Heaters

-50Temperature (°C)

105

0 50 100 150 200 250 30025

104

103

102

10

1

10-1

Rat

e of

Res

ista

nce

Cha

nge

(R/2

5°C

)

T

T

AD

BDBGBH

~

ADAE

AFAG

AH

AK

BGBH

BDBC AR AP AM

BB AS AN

Fig. 1

Temperature (°C)-20 -10 0 10 20 30 40 50 60

10

1

10-1

R/RpoRp Rs

K=2.0

K=1.0

K=0.5

Single POSISTOR(characteristic T)

R=Rp+RsRs=KRpoRpo : Resistance value

of a POSISTOR at 25°C

PTRL07BT102M2A51B0

Fig. 2 Insertion of fixed resistance in series with POSISTOR

Temperature (°C)-20 -10 0 10 20 30 40 50 60

10

1

10-1

R/Rpo

Rp

RF

h=2.0

h=1.0

h=0.5

Single POSISTOR(characteristic T)

R=Rp · RF/(Rp+RF)RF=hRpoRpo : Resistance value


PTRL07BT102M2A51B0

Fig. 3 Insertion of fixed resistance in parallel with POSISTOR

can.be.changed.as.shown.in.Fig..2.and.Fig..3..In.the.case.where.a.POSISTOR.is.used.for.temperature.compensation,.of.a.transistor.for.example,.this.method.is.useful.to.obtain.suitable.temperature.characteristics.

!Table 3 Temp. Characteristics (T.C.) and CpT.C. Cp (degC) T.C. Cp (degC)AD 280 BA 110AE 260 BB 100AF 240 BC 90AG 220 BD 80AH 200 BE 70AK 180 BF 60AL 170 BG 50AM 160 BH 40AN 150 T (−50)AP 140AS 130AR 120

5



2

2. Voltage - current characteristics (Static characteristics)

The.POSISTOR®.can.be.used.as.a.constant.temperature.heater.with.an.automatic.temperature.adjustment.function.and.can.maintain.constant.wattage,.even.over.voltage.fluctuation,.if.the.current.through.the.POSISTOR.is.maintained.above.its.maximum.current.point.The.POSISTOR.can.provide.over-current.protection.if.it.is.connected.in.series.in.a.circuit..If.current.through.the.POSISTOR.is.less.than.the.maximum.current.point.provided.as.“protective.current”.in.the.spec,.the.POSISTOR.acts.like.a.regular.fixed.value.resistor..If.current.exceeds.the.protective.current,.the.POSISTOR.will.sharply.increase.in.resistance.due.to.self.heating.and.reduce.the.current.flow,.providing.protection.to.the.rest.of.the.circuit.By.adding.a.series.or.parallel.resistor.to.the.POSISTOR,.the.voltage-current.characteristics.can.be.changed.as.shown.in.Fig..5..As.an.example,.a.resistor.in.parallel.with.the.POSISTOR.can.provide.a.constant.current.function.with.increasing.voltage.(see.curves.1,.2,.and.3.in.Fig..5.)When.voltage.is.applied.to.the.POSISTOR,.self-heating.can.occur.due.to.current.flow..If.current.flow.through.the.POSISTOR,.exceeds.the.maximum.current.point,.then.self.heating.of.the.POSISTOR.may.cause.the.temperature.of.the.part.to.exceed.the.CP.and.its.resistance.raises.dramatically..As.long.as.the.maximum.current.point.is.exceeded,.the.POSISTOR.will.stabilize.above.the.Cp.and.high.resistance.will.be.maintained..As.current.is.reduced.below.the.maximum.current.point,.self.heating.is.reduced.and.the.POSISTOR.will.cool.to.below.the.CP,.assuming.an.external.heat.source.is.not.present.With.the.voltage.-.current.characteristics.shown.in.a.double.logarithmic.graph,.the.line.(charted.as.I.vs..V).is.shown.to.increase.in.a.45.deg..straight.line.(constant.resistance.region.of.the.chart,.where.the.Thermistor’s.resistance.is.stable).until.the.maximum.current.point.is.reached..Beyond.the.maximum.current.point,.the.line.decreases.at.a.45deg.straight.line.(constant.power.region.of.the.chart,.where.the.Thermistor’s.resistance.sharply.increases).

Voltage (V)

10

10 100

100

Cur

rent

(mA)

0°C10°C25°C

40°C60°C

PTWSB2AG

Ambienttemperature

Fig. 4-3 Changing ambient temperature

2The basic design data

Voltage (V)

10

10 100

100

Cur

rent

(mA)

PTWSB

AGAH

ASBC

All POSISTORs in characteristic AR Ambient temperature 25°C

Fig. 4-1 Changing Curie point

Voltage (V)

Cur

rent

(mA)

10

102

103

1 10 100

PTGL0

7 (47Ω)

PTGL07 (

22Ω)PTGL0

9 (4.7Ω)

PTGL1

4 (2.2Ω)

PTGL1

8 (2.2Ω) All POSISTOR

characteristic : AR Ambient temperature : at 25°C

Fig. 4-2 Changing dimension and resistance value

Cur

rent

(mA)

Cur

rent

(mA)

Voltage (V)

Voltage (V)

1 1010

100

1000

1 10

1000

100

10

1. (h=2)

2. (h=3)

3. (h=5)

K=2 K=3 K=5POSISTOR

(K=0)

Ta=25°C Rs=KRpoRpo : Resistance value


PTGL07AR

PTGL07AR

Rp Rs

POSISTOR Itself (h=∞)

Ta=25°C Rp=hRpoRpo : Resistance value


RP

RF

Fig. 5 Change of static characteristic of POSISTOR by series and parallel resistance

6




2

3. Current - time characteristics (Dynamic Characteristics)

If.a.specific.voltage,.above.the.V-I.chart’s.maximum.current.point,.is.applied.to.the.POSISTOR®.a.large.amount.of.current.will.flow.through.POSISTOR,.because.its.resistance.is.low..The.POSISTOR.will.start.to.self-heat.due.to.the.current,.and.over.a.period.of.time.the.temperature.of.the.POSISTOR.will.exceed.the.Cp.and.its.resistance.will.sharply.increase..Due.to.this,.the.current.will.eventually.stabilize.at.a.constant.level..(Fig..6-1.and.6-2)If.the.initial.applied.voltage.is.increased,.the.time.needed.for.the.POSISTOR.to.self-heat.beyond.its.Cp.is.reduced,.due.to.the.larger.current.flow.causing.faster.self-heating.of.the.POSISTOR..(Fig..6-3)If.a.resistor.is.connected.with.POSISTOR.in.series.or.in.parallel,.the.dynamic.characteristics.can.be.changed.as.well..(Fig..7)

Time (msec.)

0 50 100 150 200 250 300 350 400

6

4

2

0

-2

-4

Cur

rent

Val

ue (A

)

Ta=25°C

Fig. 6-1 Current - time characteristic (AC)

Time (sec.)

0 1 2 3 4 5

8

6

4

2

0

Cur

rent

Val

ue (A

)

Ta=-10°C

25°C60°C

Fig. 6-2 Current - time characteristic(DC, Ambient temperature change)

Time (sec.)

Cur

rent

Val

ue (A

)

0 2 4 6 8 10 12

1.5

1.0

0.5

Ta=25°CPTGL09AR220M6B52B0

Fig. 6-3 Inrush current and attenuation

Time (sec.)

Cur

rent

(mA)

Time (sec.)

Cur

rent

(mA)

0 2 4 6 8 10

1000

900

800

700

600

500

400

300

200

100

0 2 4 6 8 10

1000

900

800

700

600

500

400

300

200

100

h=2

h=3

h=5

Ta=25°C Rs=KRpoRpo : Resistance value


PTGL07ARRp Rs

16V

K=2

K=3

K=5

Ta=25°C RF=hRpoRpo : Resistance value


PTGL07ARRp

RF

16V

Fig. 7 Change of dynamic characteristic of POSISTOR by series or parallel resistance

7



3

3 Structure of POSISTOR®

Leaded.products.of.POSISTOR,.as.shown.in.Fig..8,.can.have.their.POSISTOR.element.either:.soldered.to.lead.wires.and.its.surface.then.coated.with.epoxy.resin,.or.the.element.can.be.held.in.place.by.spring.terminals.and.encased.in.a.plastic.housing..In.the.case.of.the.latter,.the.spring.terminals.also.provide.the.electrical.connection.and.exit.the.housing.as.lead.terminals..The.shape.of.the.POSISTOR.can.either.be.square.or.round..Recently,.chip.type.POSISTORs.are.becoming.more.common.

Fig. 8

PRF · PRG (Bulk type)

PRG (Multi-layer type)

qBarium titanate ceramics eCoated resin tLead wire uCase oTerminalwTerminal rSoldering yCover iSpring terminal pRadiative plate & terminal

PTGL PTFM PTH6M/7M PTWSB

8



2. For Air HeatingPOSISTOR.pills.(pellets).are.mounted.in.an.aluminum.radiator.that.is.suitable.for.air.heating.The.power.and.the.temperature.can.be.easily.adjusted.by.varying.the.speed.of.the.fan.that.blows.air.over.the.radiator..Also,.its.power.characteristics.will.change.with.changes.in.ambient.temperature,.as.shown.Fig..10..When.the.ambient.temperature.decreases,.the.power.increases..When.the.ambient.temperature.increases,.the.power.is.reduced.

3. For constant temperature control:If.a.POSISTOR.is.connected.to.another.heater.in.series,.the.POSISTOR.can.be.used.to.detect.the.change.of.the.other.heater’s.temperature.and.the.change.of.the.ambient.temperature..(Fig..11)

1. Heating (Automatic temperature adjustment heater)

1. For general heaterPOSISTOR.can.be.used.as.a.constant.temperature.heater.that.is.self-regulating..It.does.not.need.a.thermostat.to.control.temperature.and.inherently.protects.against.abnormal.temperature.rise.and.failure..Constant.temperature.can.be.maintained.by.the.varying.applied.voltage.

4 Practical applications of POSISTOR®

!ApplicationsElectric.rice.cooker./.Electric.pot./.Hot.plate./.Inhaler./.Humidifying.device./.General.heater./.Antifreeze./.Fax.machine./.Copy.machine./.Portable.compact.iron./.Aromatic.instrument.and.so.on.

Surface Area of Radiative Plate (cm2)Po

wer

Con

sum

ptio

n (W

)100 200 300 500 1000 2000

10

5

3

2

1

t=5mm

t=3mmt=2mm

E=120Vr.m.s.Ta=25°CRadiative Plate : Aluminum PlateSame power marked as is obtained without radiative plate when water (20-30 cc) is supplied and boiled on the PTH.

Fig. 9 Characteristics of power consumprion

!General heaters

! Low thermal resistance type heaters capable of larger power output

Airflow (m3/sec)

0 2 4 6 8 10

0 0.25 0.5 0.75 1.0 1.25 1.5 1.75

800

700

600

500

PTWHC3AF351Y260D00 AmbientTemperature

Wind Velocity (m/sec)

Hea

t Val

ue (W

)

Applied Voltage : AC220Vrms

25℃15℃5℃-5℃

Fig. 10 Heating power characteristics of Air heater

POSISTORHeater

Heat connection

Power Source

Fig. 11 Heater control

!ApplicationsBath.dryer./.Clothes.dryer./.Futon.dryer./.Dish.dryer./.Hot-air.heater./.Auxiliary.heater.and.so.on

!ApplicationsKeep-warm.plate./.Humidifier.and.so.on

PTWLB

PTWHC

PTWTA PTWSB

PTWTA PTWSB

4

4Practical applications of POSISTOR®

9



4

2. For temperature sensor and temperature compensation

1. For temperature compensation and overheat sensing of transistors

Fig..12(1).shows.a.basic.circuit.for.temperature.compensation..In.biasing.the.transistor,.the.resistance.of.POSISTOR.is.used..If.the.transistor.overheats,.the.POSISTOR.will.heat.up.as.well..As.the.POSISTOR.passes.the.Cp,.it.will.go.high.resistance.and.unbiased.the.circuit,.and.turning.off.the.transistor..In.case.of.Fig..12(2).and.12(3),.it.also.can.be.used.as.an.over.heat.sensor.as.well.When.POSISTOR.is.used.for.temperature.compensation,.it.does.not.change.the.input.impedance,.like.a.negative.temperature.coefficient.Thermistor.(NTC.Thermistor),.because.the.POSISTOR.is.not.connected.to.input.circuit.in.parallel..Therefore,.the.POSISTOR.is.suitable.for.circuits.which.do.not.need.a.change.of.input.impedance.as.a.pulse.circuits,.regional.amplifier,.and.measurement.equipment.

More.than.two.pieces.of.POSISTOR.can.cover.multi.hot.spots.working.with.a.comparator..Fig..12-2.shows.basic.circuit.idea.to.connect.multiple.POSISTOR.in.series..When.One.POSISTOR.detects.overheat.at.least,.a.comparator.can.work.by.the.sharp.temperature-resistance.characteristic..It.easily.allows.changing.a.number.of.POSISTOR.or.sensing.temperature.in.the.same.basic.circuit.design.

2. Overheat sensing for motors and transformers

A.POSISTOR.can.be.used.for.the.overheat.sensing.of.motors,.transformer.winding,.bearings,.power.transistors,.and.other.machinery..Fig..13(1).shows.an.example.of.overheat.sensing.for.motor.using.a.relay..In.case.of.small.regular.operating.current,.the.circuit.can.be.directly.stopped.by.POSISTOR..In.case.of.larger.regular.operating.currents,.the.circuit.can.be.stopped.by.using.the.POSISTOR.with.a.relay.or.a.thyristor..In.either.case,.POSISTOR.is.a.very.easy.to.use.device,.because.it’s.small,.light,.and.a.two.terminals.device.

(1)

POSISTOR

R’B

RA

POSISTORRL

RE RE

(2)

POSISTOR

RB

RA

RL

(3)

RB

RA

R’L

Fig. 12 Temperature compensation and protection of transistor

POSISTOR

POSISTOR

M

POSI

STO

R

Pow

er S

ourc

e

PowerSource

Motor (1) Power Transistor (2) Transformer (3)

PowerTransistor

Relay

Fig. 13 Protection from overheat by POSISTOR

PTC1

R1R4

V+in

V–in Comp Out

R2

R3

PTC2

PTC3

PTC4

Vcc

Vcc

+

–Comp

Fig. 12-2 Connection of multiple POSISTOR


PTFM04 PTFL04

For overheat protection of power transistor or IC

PRF18/15

10



POSISTOR

POSI

STO

R

20KΩ

Neon Lamp

100V60Hz

Neon Lamp

100V60Hz

20KΩ

(1) (2)

Fig. 14 Temperature indication by POSISTOR

PTGL PTRL

For temp. indication, overheat protection

3. For temperature indicationFig..14.shows.most.simple.example.of.a.temperature.indicator..Temperature.is.sensed.by.POSISTOR..If.the.target.temperature.is.exceeded.(determined.by.which.POSISTOR.is.used),.a.neon.tube.lights.up.

4

4 Practical applications of POSISTOR®

11



4


1. Over current protectionIf.a.circuit’s.current.limit.is.exceed,.a.POSISTOR.can.react.to.the.higher.current.(self.heating).and.quickly.protect.the.circuit..(Fig..15)

3. For current control

Thyristor

POSISTOR

Fig. 17 Inrush current limit circuit

PowerSourcePOSISTOR

Rel

ay

Rel

ay

Rel

ay

R TimeAdjustment

POSISTOR POSISTOR

For Heater

ForDelaying

(1) (2) (3)

Fig. 16 Delay operation of relay

POSISTOR

PowerSource

PowerSource75Ω

100KΩ

10KΩ

POSISTOR

Transistor (1) Motor (2)

Power circuit (3)

160V 30µF

0.1µF

POSISTOR

27Ω

2.2Ω

160V 30µF

Antenna

Coaxial Cable

POSISTOR

-BRL

100KΩ

10KΩ 10µF

-BRL

MPower Source

Motor

POSISTOR

POSISTOR

T.V Booster

Fig. 15 Protection from over current

(1)RSI Motor

(2)CSIR Motor

(3)CRS Motor

(4)PSC Motor

Fig. 18 Motor starting

PTGL04 PTGL07 PTGL12

PTGL

2. Delay CircuitA.delay.function.can.be.created.by.using.the.dynamic.characteristics.of.POSISTOR..There.are.two.methods:..one.is.with.the.POSISTOR.connected.in.parallel.with.a.relay.as.in.Fig..16(1).and.the.other.is.similar.but.with.series.connection,.as.in.Fig..16(2).and.(3).

3. For the control of inrush currentA.switching.power.supply.has.large.inrush.current.when.it.first.turns.on..If.POSISTOR.is.used,.instead.of.a.resistor.or.an.NTC.Thermistor,.the.POSISTOR.works.as.inrush.current.limiter..The.POSISTOR.self.heats.due.to.over.current.in.the.case.of.relay.or.thyristor’s.failure.and.will.trip.to.high.resistance,.quickly.shutting.off.the.current..(Fig..17)

4. For motor starterIf.the.POSISTOR.is.used.as.a.contactless.starter.rely,.for.compressors.as.in.refrigerators,.freezers.and.air.conditioners,.strong.starting.torque.can.be.generated..(Fig..18(1).to.(4))

PTH6M PTHTMPTH7M

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5

5 Terms

Definitions.of.typical.terms.for.POSISTOR®s.are.listed.here.

1. Initial resistance (R25)This.is.the.part’s.resistance.value.at.25degC.which.is.measured.under.conditions.of.1.0VDC.or.less,.and.10mA.or.less.without.self-heating.

2. Curie point (C.P.) temperature (Resistance - temperature characteristics)

A.POSISTOR.maintains.almost.the.same.resistance,.until.certain.temperature..After.this.temperature.is.exceeded,.the.resistance.of.POSISTOR.rises.up.sharply..This.transition.point.is.called.the.“Curie.point”.or.“C.P.”..Murata.defines.this.critical.temperature.to.be.the.‘Curie.point’.temperature,.where.the.actual.resistance.value.is.twice.the.reference.value.measured.at.25degC.

3. Maximum operating voltageWithin.the.operating.temperature.range.of.POSISTOR,.it.is.the.largest.voltage.that.can.be.applied.continuously.

4. Withstanding voltageThe.maximum.voltage.which.the.POSISTOR.can.withstand.over.a.three.minute.period,.at.25deg..To.test,.the.input.voltage.is.raised.to.withstanding.voltage.from.zero.voltage.gradually..

5. Heat dissipation factor (D)It.is.the.amount.of.heat.which.is.lost,.over.a.unit.of.time,.based.on.1degC.temperature.difference.between.heating.element.and.ambient.temperature.

W=I.·.V=D(T–T0)

T:.. temperature.of.heating.elementT0:..ambient.temperatureD:..heat.dissipation.factor.(W/degC)

Generally.this.value.is.decided.by.a.size,.a.structure.and.material.of.heating.element.

6. Thermal time constant (γsec)It.is.the.time.needed,.to.achieve.0.632.times.the.temperature.difference.between.T0.to.T1.γ=H/D,.Here.D,.Heat.dissipation.factor.(W/degC),.H:.Heat.capacity.(Wsec/degC).This.formula.is.related.to.dynamic.characteristics.

7. Operation pointIt.is.an.equilibrium.condition.between.self-heating.of.the.POSISTOR.and.the.external.radiator..

!Strict observance:

POSISTOR.is.not.hermetically.sealed,.do.not.use.it.under.the.below.conditions..If.POSISTOR.is.used.in.such.conditions,.they.may.cause.decline.of.characteristics.or.may.lead.to.short-circuit.type.failure.·..Corrosive.gas.atmosphere.(Cl2,.NH3,.SOx,.NOx.and.so.

on)·..Volatile,.flammable.gas.atmosphere·..Dusty.area·..Pressurized.air.or.vacuum.atmosphere·..Direct.contact.with.water,.standing.water.on.the.part,.

or.high.humidity.·..Exposure.to.salt,.grease,.chemicals,.organic.solvents·..Place.with.a.lot.of.vibration·..Anything.equivalent.to.the.above.mentions

!Notice:POSISTOR.should.be.evaluated,.after.confirmation.of.rated.value,.and.using.precautions.as.given.in.the.catalog.

PTC Thermistor (PPOSISTOR(R)) - Jameco Electronics APP Catalog.pdf · for EU RoHS Compliant • All...

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Transcript of PTC Thermistor (PPOSISTOR(R)) - Jameco Electronics APP Catalog.pdf · for EU RoHS Compliant • All...