16
ir, ffi n il il il il il il il il il il il il il il il Experiment, g BIPOLAR .TI'NCTTON TRAI{SISTOR DC BTASTNG CONFIGURATIONS OB.fECTIVES To determine the quiescent operating conditions of fixed-bias , emitter-stabilized bias and. volt.age divider bias BrtT configurations To provide an additional insight into Ehe choice of an operating point of a DC bias circuit using the graphical_ method. IIiIlf RODUCTORY INFORMAT I ON Transistors may be connected in three possible arrangements as shown in figure 8.1. These are r (1) common_emitter connection,. (Z) common-base connections,. and (3 ) common-co]l-ect,or connecLion. The connection depends on which t.ransistor terminal it is- connected to both bias supplies. Each of Lhese circuit connections has specific advantages in some applications, but the common-emitter connection is by far the most widely used, part.ly because it is capable of more power gain t.han the others. (a) (c) Figure 8.1 (a) cornmon emitter amplif ier; (b) common common collect.or amplifier BASETLA Experiment Manual Experiment B: B,JT DC Biasing Conf igttratir:ns Page 1 of 1"4 base arnplifier; (c)

Electronics Lab Manual Bipolar junction transistor

Embed Size (px)

Citation preview

Page 1: Electronics Lab Manual Bipolar junction transistor

ir,

ffi

nilililililililililililililil

il

Experiment, g

BIPOLAR .TI'NCTTON TRAI{SISTOR DC BTASTNGCONFIGURATIONS

OB.fECTIVES

To determine the quiescent operating conditions of fixed-bias ,emitter-stabilized bias and. volt.age divider bias BrtT configurations

To provide an additional insight into Ehe choice of an operatingpoint of a DC bias circuit using the graphical_ method.

IIiIlf RODUCTORY INFORMAT I ON

Transistors may be connected in three possible arrangements asshown in figure 8.1. These are r (1) common_emitter connection,. (Z)common-base connections,. and (3 ) common-co]l-ect,or connecLion. Theconnection depends on which t.ransistor terminal it is- connected to bothbias supplies. Each of Lhese circuit connections has specificadvantages in some applications, but the common-emitter connection isby far the most widely used, part.ly because it is capable of more powergain t.han the others.

(a)

(c)

Figure 8.1 (a) cornmon emitter amplif ier; (b) commoncommon collect.or amplifier

BASETLA Experiment ManualExperiment B: B,JT DC Biasing Conf igttratir:nsPage 1 of 1"4

base arnplifier; (c)

Page 2: Electronics Lab Manual Bipolar junction transistor

!t

;

ilMany voltages and currents in a circuit, cont,aining a transistor

are imporLant. in its operat.ion. The notation for operating currentsand voltages of Lhe B,JT are present.ed in tab]e 8.1. rn order todistinguish easily a particular voltage or current for d,iscussion or torepresent it in ar1 equation, letter symbols have been adopted assymbols for these cj-rcuit parameters. Uppercase l-etters are used forquantities that are constant, while l-owercase letters denote quantit,iesthat can vary in va1ue. subscripts are also used to distinguishvarious circuit parameters that. are symbolized by uppercase andl-owercase l-etLer symbols.

Table 8.1. Transistor Current and Voltage Symbols

ilililililililil1

fiilr

ilr

ili

f,!

Ir

fB

ibiBrcjJ-g

r ceo

Vc,vce

vca\7" ce

vccVee

Va1ue of dc component of base current, its averagevaluefnstantaneous value of ac component of base currenLInstantaneous toEal base currentValue of dc component of collector currentInstantaneous toLal collector currenLReverse collector-to-base current when emitter isopen- c j-rcuitedAverage voltage beLween co1lector and emitt.erfnstantaneous val-ue of ac component of collector-emitter voltageInstantaneous total colfector-emitter voltageRMS value of ac component of col-Iect-or-emittervoltage,' rms of v..Supply volt.age for col1ector circuitSupply voltage for base circuit

There are generally two methods of evaluating a transistorcircuit. The equivalent method, used by the design engineer andsometimes cal1ed the analytical- method, involves many mathematical-computations. The graphical method presents a picture of the operatingcharacLeristics of the circuit as Lhe transistor is used with any valueof Load resistance. By using Ohm's Law, Kirchoff's Law and the basicpower equation you will have a visual presentation of the operationallimits of the transistor as specified by Lhe manufacturer.

For amplification with arr undistorted output signal and linearvoltage gain, the transistor shouLd be biased in Ehe finear or activeregion. To do this, Lhe base-emitter junction shoufd be forward biasedwhile the base-collector junct.ion shoufd be reverse biased. BiasingesLablishes a certain currenL and voltage condition in a transistorcalled a dc operating point, quiescent point or Q-point.. For a B.IT,this point is defined bY V6s and Is.

BJT DC Analysis

il_I

,'

. GR,APHfCAL METHOD

A common-emitter amPlifier ascurrenL gain; Lypical range of which

BASETLA Experiment ManualExperimenL B: BJT DC Biasing ConfigurationsPage 2 of 1"4

shown in Figure 8.2 Provides highis from 20 to 200.

Page 3: Electronics Lab Manual Bipolar junction transistor

il

il

il

il

il

il

il

il

ilill,tF

Figure 8.2

The out.put loop equation of the circuit is a straight line in a

voltage and current ploL as shown:

-1 VccT - \r-- f ---- \ + -----rc - vcE \ /

Rc Rg

(Equation 8.1)

where: * the ordinate (y-axis) is the collector current Ic* t.he abscissa (x-axis) is the collector-emitter currenL VcE

* the slope is -t/R"* Vcc/Rc is the Y-intercePt

The st.raight line representing Equation 8.1 can be drawn byd.ef ining two extreme PoinLs:

1' Set Ic = O, Vce = Vcc condition for cut-off2. Set V6" = Q, Ic = Vcc/Rq condiLion for saLuraLion

Equation B. l- is called the "DC load line equation" fot thecollector circuit. When Lhis equation is plottsed on Lhe outputcharacLeristic curveB, the resulting straighb line is cal1ed the DC

load line for the circuit. The points shown in Figure B ' 3 and thestraight line connecting them is cafled the Dc l-oad fine. The foadline depends only on the supply voltage, Vcc, and the value of thecolfector resistoi, R6. Furthermore, as long as the DC-operaLing pointis within the extreme points defined above, the transistor is oper:atingin the linear region.

I C, xt.[,

vcc/Rc DC load line

vcc Vg3, volts

Figure 8.3

The foad line is constructed between the point of minimum

cofl-ector voltage with Ehe maximum collector current and maxintum

BASETLA ExPeriment Manua1Experiment 8: B,JT DC Biasing ConfigurationsPage 3 of 14

Page 4: Electronics Lab Manual Bipolar junction transistor

I

collector voltage with minimumline, you can determine all- ofbe employed.

. ANALYTICAL METHoD

col-]ector current,. From the construct.edthe possible operat.ing points t.hat can

il

il

Iil

il

il

il

tIil

T

T

II

Another method of eval-uating transisEor circuit is the analygicalmet'hod Ehat involves the basic transistor formulas. These mar-hemat.icalequations shows the relationship of rg, rc and fE when the transisLoroperates in t.he active region.

Applying KCL to t.he transistor,

where rs is the emitter current ," ,,,1"rrr:rlf,.lj'Ic is t.he col_lector current in milliamperesfB is the base current in microamperes

Under DC condit.ion,

on" : 4-"AIr

o is def ined as f ol]ows:

CTDC : IC

IE

(Equation 8.2)

transistor is forward

(nquation 8.3)(Eguation 8.4)

(Equation 8.5)

(.Equation 8.6)

fn transistor data

When the base-emitter junction of thebiased, the base-emitter voltageVsB : 0.7 V for NpN , Si transistorVnn = 0,7 Y for pNp, Si transistor

The relationship between the collector current ancl emi-ttercurrent due to majority carrier is expressed through the common-baseshort' circuit amplification factor, q. under AC condit.ion, o isdefined as the ratio of Lhe change in collector current to the changein emitter current. fn equation form,

The typical val-ue of . o ranges from 0.9 to 0.998sheeE, o is referred to as hon.

I

rn solving for the DC colfector current in terms of o,T

- -- TLc - u DC tE (Equation 8.7)

The relationship between the coll-ector current and base currentdue to majority carriers is expressed Lhrough the common emitterforward current amplification factor, B. under AC condition, p isdefined as the ratio of the change in collector current Lo the changein base current.. fn equation form,BASETI,A Experiment ManualExperiment 8: BJT DC Biasing ConfigurationsPage 4 of 1-4

Page 5: Electronics Lab Manual Bipolar junction transistor

il

Iil

il

IIil

il

il

n

lr

I'

Under DC condition, B is defined as

opDC =

oo"=ff (Equation B. B)

(Equation 8.9)

fn transistor data

follows:IC

IB

The typical value ofsheet, F is referred t.o

B ranges from 5Oas h"r.

to 400

Otrms

fn solving for t.he DC col-lector current j_n terms of F,

I. : /J orl, (Equation 8.10)

DC Biasing Configuration

fn this experiment,configurations namely theCircuit and Vo1t.age Divider

FTXED BIAS CIRCUTT

we will investigateFixed Bias Circuit.,Bias Circuit.

three BJT DC biasingEmitter-Stabilized Bias

The connection of a fixed biasFor this bias configuration, the baseresistance Ra. Therefore, a variationchange in the collector current. andtransisEor. For this reason, it canexact locat.ion of the e_point onconf igurat.ion.

Rg56OK Ohms

circuit is shown in figure g.4.current is held fixed by the basein B and temperature wiII cause acolfector-emitter voltage of thebe very difficult. to predicr. thethe load 1ine of a Fixed_bias

+Vcc = 20 vRC2.2K

1r*

v". - 0.7 YRB

I r]..* ?

(Equation 8.11)

,;-.itr'-f: ' l'-t

'+vcr

ll,,

Figure 8.4

For a Fixed- Bias circuit, the DC base current i-s computed as

, -V." -V".lD - -_=---:- ="RB

BASETLA Experiment Manual_Experiment B: B,TT DC Biasing ConfigurationsPage 5 of L4

r*

10 -b${z D,;tlir

'7

Page 6: Electronics Lab Manual Bipolar junction transistor

j*'*r'

If:

f,

Iil

il

IIIIII

I

I

The DC emitter

The coflectorby setting Vce

Rs560K ohms

For an emitter-stabil_izedca]culat,ed as

BASETLA Experiment Manua1Experiment B: B,JT DC niasingPage 6 of t4

ilr"r", for the DC cot_lecror_emitter voltage of

V"u =V"" - I" R" =V"c -flrR"current is obtained by applying xCL

I, :I" *Iu = fl, +\ = (f+1)IB

saturat,ion l_eve1 for the transist.ort.o 0V,

, -V..'.f'u, - EIThe maximum colrect.or-emitter voltage for the transi_stor amplifier is!f,::iffi J.rrr:""", the transisror ro "rt-oir. when r" ='-o A rrom

V"u1org/ : Vcc (Equation 8.15)

the Lransistor resu.lts

(Equation B.12)

to the transistor,

(Equation 8.13)

amplifier is obtained

(Eguation 8.14)

+vcc = 20 v

8K Ohms

. EMTTTER-STABTI,IZED BTAS cIRcuIT

The emitter-stabilized bias configuration in figure 8.5 containsemitter resistor, RE to i-mprove :1. "trritrty over that of the fixedbias configuration. with the addition of R;, there wirl be a smallvariation in the dc currents and voltages of the transistor even whenthe temperature and transistor B changes.

I{"CL.

Jr"

+!rBE_

RE1- K Ohms

'+Ycr

I

I1'"

Figure 8.5

bias circuit, base current

Configurations

the 1S

Page 7: Electronics Lab Manual Bipolar junction transistor

ry

Ir= V.. - V". v.. - 0.7 VRn +(/+1)RE R" +(/+1)RE

fla"r"n for rhe DC cot lecror_emirter volrage of

V"u:V"" - I. R" -IuRu =V"" - fl" R" _(F+

The collector saturation 1evel" is computed as

r-V..r clsat) - -------=-R" + -ta

aThe maximum collector_emitt.er voltage for theobtained by driving the t.r.r"i=tor to cut_offequat,ion B.1T is set to 0 A,

V.u1orrl = V.c

(Equation B.1G)

the transistor results

I)IBRE (Equarion 8.17)

J-'t(Equation B. LBJ

. VoLTAGE DTVIDER BTAS CTRCUTT

rn fixed-bias and emitter-stabir-ized bias configuration, the DCoperating collector- current, rsp and the DC operating -correcitr-emittervoltage, Vcne of the transist'or is aepenaeit on B. Since p isi"T:""1":"""i:i:::'? :", increase in rlmperarure will chanse rco andwh i c h i s

" r *o

" .'. "l,.li. jj"T. r"1i" lil . .::: "

Lr".: r;

: :",*"".JI;" ;j.t. H:Voltage Divider bias configuration srrorn i;-;;;".e B.d, even though rheleve1 of rao changes ,h;a p changes, the -operating point on the

;:#::':l:::i; "',1;".:;T:'S"":1

rhJ-;". ";; v.,e remains consranr ir

transistor amplifier is. When f. and fB from

(Equation 8.19)

+vcc = 2,a vR.C1 .2K OhmsRnt

sOK Ohms

RgaL5K Ohms

BASETLA Experiment ManualExperiment 8: B,tT DC BiasingPage 7 of 1"4

?

Y $V' V'p *

v{, ,{&

1r"+ltcr

r-gure 8.6

figurations

*.t1'"I r " orrms

F

Con

Page 8: Electronics Lab Manual Bipolar junction transistor

For the voltage_divider bias circuit, applying theto figure 8.5, the DC t ""e ,o:_tlge of the circuit isV : Vtc Rn''B-R,*R,

Knowing the value of Vr, VE can be sol-ve using the

VE:V, -Vns =VB -0.7VBY Ohm's Iraw, the DC emitter current

r-:fL"R-Since DC base current, f" is too small, Ie ! Ic.The DC coflector-emitter voltage of the transi-stor resurts to

vru:v"" - I" R" -IuRu =vcc -I"(R. *Ru) ("nr"rion e.23)The maximum DC collector current for .he transistor in a voltagedivider bias configuration is obtained by a.iri.rg the transistor tosaturation. From equation 8.23, when Vqr1._.1 is set to 0 V

T-V.",c1sat1 R. . Ru

The maximum collector-emi-tter voltage for the transistor in a voltagedivider bias configuration is obtained by driving the t.ransistor tocut-off. From equation g.23, when Is = 0 A,V"oton) : Vcc

voltage divider rul_ecomputed as

(Equation 8.20)

equation

(Equation B.2t)

(Equation 8.22)

(Equat,ion . B.Z4)

(Equation 8.25)

MATERTAIJS REQUIRED

r 1 - DC Regulated powert 2 -AnalogVOM/Digitalr 1-560K0resistorr 1-30KeresistorI 1- l_5Ke resistorr 1- 2-2KA resi.stor. 1 - l_.8KA resistorI 1 - 1.2KA resistorr 1-lKeResistorr 1 - 2N3904 NpN Bipolarr1-CurveTracerr 1 - Breadboard! Connect,ing Wires

SuppIyvoM

.Tunction Transistor

BASETLA Experiment ManuafExperiment B: B,JT DC Biasing ConfigurationsPage I of 14

Page 9: Electronics Lab Manual Bipolar junction transistor

2 ' Measure v"" and rs of the circuit. Note i-t down in table 8.23' compute for the r" of the circuit

-uging equation 8.11. use themeasured Vs, and Rs, Note it down in tabl_e B .24' compute for B using equation 8.9. This is value of B will be usedfor the 2N3904 transislo.ttfr.""girout the experiment.

PROCEDURE

FTXED-BIAS CTRCUTT

1. Connect, the circuitof the resist.ors to be

Measure t.he act.ual valuesshown in figure B .4

used.

Tabl.e B . 2

Graph 8.1

ConfiguratLons

RB (measured) = f't\ VslRc (Mesaured) = _j4#-

B= 0-1

5. Measure thetransisro' "i..".,i?:

"^n:".'ffi H:t;:i:"=*iX ."*Ji""T. r:t r-he rixed-bias

6 ' compute for the theoreticaf values of the DC operating voltages andcurrents of fixed bias circuit usi'g the equat.iorr= presented in theintroductory information. Note down the values in tabr-e 8.2.

fi"""llfX:i.:", rhe sarurarion levet and cur_off fevel of rhe fixed_rcsur = f"ucl l"\ fa

vc" (ort)

7. Using the curve tracer, obtain2N3904 NpN transistor. pfot it on

n " /,rW V

the characteristic curve of thegraph 8.1.

BASETLA Experiment. ManualExperiment B: BJT DC BiasingPage 9 of L4

Measured value Theoretical vi-tue & difference

Page 10: Electronics Lab Manual Bipolar junction transistor

B. Obt.ain t.he DC ]oad l-ine of theusing the equat.ion presented in the

9. What is the region of operation

circuit on the characteristic curveintroductory j-nformation

of the transistor?EMITTER-STABTLIZED BTAS CTRCUTT

10. Connect the circuit shown in figure 8.5.l-1 ' Measure the. DC operating voltages and current of the fi-xed_biastransistor circuit. Not.e dowi the va]ues in t.abf e 8.3 .

12. compute for the theoreticar varues of the DC operating voltages andcurrenLs of emi-tEer-stabirized bias circui-1 using Lhe equations:ffi:";:i.

," rhe inrroducrory inf ormariorr. *o." down rhe values in

level and cut-off leve1 of

/1.,I A-_-=\= "LL/'

74. What. is t.he region of operation of t.he transist.or?VOLTAGE-DTVTDER BTAS CTRCUIT

15. Connect the circuit shown in figure 8.6.1'6 ' Measure the DC operating voltages and current. of the voltage_divider bias transistoi circuil . Note down .he var.ues in table 8.4.1"7 ' compute for the theoretical values of the DC operat.ing voltages andcurrenLs of emi-tter-stabirized bias circuit using the equationspresented in the introduct.ory informat.ion. Note down the vafues intable 8.4 .

BASETLA Experiment ManualExperiment B: BJT DC Biasing ConfiguL-ationsPage 10 of L4

13. Compute for Lhe sat.urat.ionstabilized bias circuit. Lhe emitter-

Ic""t

Vce (ort )

tr:B

ff

TableMeasured vafue Theoretical value & differenee

TableMeasured value Theoretical vafue & difference

Page 11: Electronics Lab Manual Bipolar junction transistor

]II.;

ilI

;i

i:it

il

I

rl;lrliilil}riiiJ

1i

ir

ii

I

I

il

il

il

il

il

il

il

III

i

ta

)

II

i

ii18. Compute for the saturationstabilized bias circuit.

]evel and cut-off leve] of the emitter-

= fi;l*KAL

fcsat

Vc" (otr)

19 what is the region of operation of the transistor?

BASETLA Experiment Manual-ExperimenE 8: BLTT DC Biasing ConfigurationsPage l-l- of 14

GUIDE QUESTIONS

l-. What is the purpose of the DC load l_ine?2 . Describe the ..e,, point.3 ' Describe what happens when you increase the varue of roadresisLance if t,he collector supply voltage remains constant.4. What is biasing?5 ' why is the transistor carled a current-controlr-ed device?6' would you say that transistors are temperature sensitive? Explain.7. What is meant by the st.ability factor of a circuit.?8. What is a? what is Bz What is ya Explain briefly.9' Answel: the computer simulation probleis in.Exerc:se B..DEsrcN oFBJT DC BTASING CTRCUIT

t

Page 12: Electronics Lab Manual Bipolar junction transistor

IExperiment 7: BIPOLARPreliminary Report

Laboratory fnstructor :

Date Performed:

Group Leader:Group Members:

.TI'}TTCTION TRANSISTOR DC BIASING CONFTGURATIONS

, i4ti. '-

:

It

I

n

k

Grade:

fnstructor, s Sigiiq,tu.re :lrrlz

ll

Dat.a and Results:

FTXED-BfAS CIRCU]T

1' connect' the circuit shown in figure 8.4. Measure the actua] valuesof the resistors to be used.RB (measured) = j-q,fK.fLRc (Mesaured) = --A.*7Tfn-

2 ' Measure V"" and rg of the circuit. Note it down in table 8.23 ' compute for the rB of the circuit using equation 8.11. use themeasured vus and Rg. Note it down in table d.z'4' compute for p using equation 8.9. This is varue of B will be usedfor the 2N3904 transisior throughout -the experiment.

B =-__La+::'-5' Measure the .DC operating voltages and current. of ,/"nu fixed-biastransist.or circuit.. Not.e dor.^in the values in t.able B .2.6 ' compute for the theoreticar- values of the DC operat.ing voltages andcurrents of fixed bias circuit. using the .qr.tio.r= presented in theintroductory information. Note down the values in table 8.2.

5' compute for the saturation r-ever and cut-off level of the fixed_bias circuit.rcsar = ?" l|n#

BASETLA Experiment Manuaf iExperiment B: B,jf DC Biasing ConfigurationsPage 12 of 1_4

Table B.2Measured vafue Theoretical value & difference

|':

i{,lr1

Page 13: Electronics Lab Manual Bipolar junction transistor

l-8. Compute for the saturationstabilized bias circuit

1".1

3.

4.5.6.7-B.9.

BASETLA Experiment Manual-Experj-ment 8: BJT DC Biasing ConfiguratjonsPage L1 of i"4

LeveL and cut-off Level of the emiLter-

fc"at =

Vce (ott)

19. What is the region of operation of the transistor?

GUTDE QUES"IONS

thra i: rhe purpoee of rhe DC toad tine?Describe the ',e,, point..Describe what happens when you increase the value of r-oadresistance if the collector supply voltage remains constant.What is biasing?why is the transistor car-led. a current,-controlr"ed device?would you say that transistors are temperature sensiti.ve? Explain.what is meant by the stability factor of a circuit?What, is cx? Whar is Bz What is y? Explain briefly..#ff;:;".tnt

computer simulation problems in Exercise B : BJr Dc

,.:,i. ,irl-,1jl

',,I: .1.11 1

r +oi.,i

Page 14: Electronics Lab Manual Bipolar junction transistor

il

tililililililililil

iI

f***"i

vcs (otr l

7. Using the curve tracer, obtain2N3904 NpN transistor. plor-i;-o.,

= *n/?t\) t

the characteristicgraph 8.1.

curve of the

Graph 8.18 '" obtain the DC r-oad r-ine of the circuit. on the characLeristic curveusing the equation presented in the introauctory information.9. what is the region of operation of the transistor?EMTTTER-STABTLTZED BTAS CIRCUTT

1L' Measure the. DC operaLing voltages and current of the fixed_biast.ransistor circuit. Note Aowi tne values in table 8.3.72. compute for the theoreticar- va]ues of the DC operating vortages andcurrents of emitter-stabir-ized bias circuil using the equationsiffi:";:i. '" rhe inrroducrorv inf ormarion. lrote down rhe values inI

tI

I13. Compute forstabilized bias

the saturationcircuit.

fevel and cut-off ]eve] of the emitter-

rcsat = c i/ftvcB(otr) = flfi t/

!4. What is the region of operation of the traFsistor?/

BASETLA Experiment ManualExperiment B: BLTT DC Biasing ConfiguratLonsPage 13 of 14

Tabl.eMeasured value Theoretical val-ue & difference

Page 15: Electronics Lab Manual Bipolar junction transistor

VOLTAGE-DIVIDER B1AS CIRCUTT

1'6 ' Measure the DC operat.ing voltages and current of .he voltage_divider bias transistor circuii. Note down the varues in table 8.4.L7 - compute for the theoret.icar- var-ues of the DC operating voltages andcurrents of emitter-stabilized bias circuit using the equationsi:;i:"::i.

," Ehe inrroducrory informarion. Nore down rhe vatues i4

l"B. Compute for the saturation levelstabilized bias circuit.and cut-off leve1 of the emit,ter_

/st19

vco (orr) =

What is the region of operation

rcsat = 4 t,*ll

of the transi

dat/

or?

!

Ij

.lil

rjrjil

i

BASETLA Experiment ManualExperiment B: B.TT DC Biasing ConfigurationsPage 14 of t4

iiL{

r$,

fl:r

il

iI

TableMeasured value lheoret.ical value & difference

Page 16: Electronics Lab Manual Bipolar junction transistor

[- ifi

*

Z.

DEsrcN o" "otI";:riiolr*n crRcurr

Design an emir

: ?r*A, ;. #'JJ..J "ii*i;,:?.:^f:,,t.;;,;E.:".1:"1:? ;;.j;: :f7.62v. use a L6 v jc lir^nr, irJ_ _ui _),irrr2

NpN siii.o,,ffiff;ff";. ,,:::.JI:l;,i- uir"f;. - ,i*,r"J. ;:,,, circuir usins

l-::iS" a voltage divider bias ci rr,, j + .,^r -2N2222 NpN alri"on rransisro_"il:y1a using a suppry of 24v,

iff , !i::ol?i"' .::, i;:ii lil":"J' -1' : iT'' tn."'" "' U =: +: "; ;:simur.are your cirquit uslns ;;;?:;, ,.rr.S"r.1fjJJ,.i*rr.

-;;;fi.