ec2155 - circuits & devices lab manual

7/28/2019 EC2155 - Circuits & Devices Lab manual

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EC2155-CIRCUITS AND DEVICES LAB

M.A.M SCHOOL OF ENGINEERING

Siruganur, Trichy-621105

DEPARTMENT OF ELECTRONICS AND COMMUNICATION

ENGINEERING

LAB MANUAL

Subject Code: EC2155

Subject Name: CIRCUITS AND DEVICES LAB

Year/Sem: I/II ECE

LIST OF EXPERIMENTS

1. Verification of KVL and KCL

2. Verification of Thevenin and Norton Theorems.

3. Verification of superposition Theorem.

4. Frequency response of series and parallel resonance circuits

5. Verification of Maximum power transfer and reciprocity

theorems.

6. Characteristics of PN and Zener diode

7. Characteristics of CE configuration

8. Characteristics of CB configuration

9. Characteristics of UJT and SCR

10. Characteristics of JFET and MOSFET

11. Characteristics of DIAC and TRIAC.12. Characteristics of Photodiode and Phototransistor.


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1.VERIFICATION OF KVL & KCL

AIM:

To verify (i) kirchoffs current law (ii) kirchoffs voltage law

(i) KIRCHOFFS CURRENT LAW:COMPONENTS REQUIRED:

Sl.No components Range Quantity

1

2

3

4

5

RPS

Resistor

Ammeter

Bread board

Connecting

wires

(0-15)V

1 K

(0-10)mA

------

------

1

3

3

1

few

THEORY:

krichoffs current law:The algebraic sum of the currents entering in any node is Zero.

The law represents the mathematical statement of the fact change cannotaccumulate at a node. A node is not a circuit element and it certainly cannot

store destroy (or) generate charge. Hence the current must sum to zero. A

hydraulic analog sum is zero. For example consider three water pipes joined

pn the shape of Y. we defined free currents as following into each of 3

pipes. If we insists that what is always

CIRCUIT DIAGRAM:

1. Kirchhoffs current law:

1.0k 3.3k

5V 4.7 K

Kirchoff`s current law

Practical measurement:

1.0k 3.3k

5V

4.7 K

A A

A

+ - + -

+

-

(0-20)mA (0-10)mA

(0-10)mA


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TABULATION:

Voltage Total currentI(mA)

I1(mA) I2(mA)

PROCEDURE:

1. Connections are made as per the circuit diagram.2. Check your connections before switch on the supply.3. Vary the regulated supply.4. Measure the current using ammeter.5. Note the readings in the tabulation.6. Compare the observation reading to theoretical value.

ii) KIRCHOFFS VOLTAGE LAW:

COMPONENTS REQUIRED:


1

2

3

4

5

RPS

Resistor

voltmeter

Bread board

Connecting wires

(0-15)V

1K,2.2K,3.3K

(0-20)V

------

------

1

Each 1

3

1

few

THEORY:

(i) Kirchhoffs voltage lawThe algebraic sum of the voltage around any closed path is zero.

The law represents the mathematical statement of the fact change cannot

accumulate at a node. A node is not a circuit element and it certainly cannotstore destroy (or) generate charge. Hence the current must sum to zero. A

hydraulic analog sum is zero. For example consider three water pipes joined

pn the shape of Y. we defined free currents as following into each of 3

pipes. If we insists that what is always


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CIRCUIT DIAGRAM:

Krichoffs voltage law:

Kirchoff`s voltage law

1.0k 3.3k 2.7k

5V

V1 V2 V3

Practical measurement:

1.0k 3.3k 2.7k

5V

V V V+ - + - + -

(0-5)V (0-5)V (0-5)V

Practical measurement

TABULATION:

Voltage

(V)

V1

(volts)

V2

(volts)

V3

(volts)

PROCEDURE:

1. Connections are made as per the circuit diagram.

2. Check your connections before switch on the supply.3. Vary the regulated supply.

4. Measure the voltage using voltmeter.5. Note the readings in the tabulation.

6. Compare the observation reading to theoretical value.

RESULT:

Thus the Kirchhoffs current law and voltage law were verified.


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2.VERIFICATION OF THEVENINS THEOREM

AIM:

To verify Thevenins theorem and to find the current flowing through the loadresistance.



1

2

3

4

5

6

RPS

Resistor

Ammeter

voltmeter

Bread board

Connecting wires

(0-15)V

1K,2.2K,3.3K

2,7K

(0-5)mA

(0-5)V

------

------

1

Each 1

1

1

1

few

THEORY:

Thevenin`s theorem:

Any linear active network with output terminals can be replaced by

a single voltage source Vth in series with a single impedance Z th. Vth is the

Thevenin`s voltage. It is the voltage between the terminals on open circuit

condition, Hence it is called open circuit voltage denoted by Voc. Zth is

called Thevennin`s impedance. It is the driving point impedance at the

terminals when all internal sources are set to zero too.

If a load impedance ZL

is connected across output terminals, we can

find the current through it IL = Vth/(Zth + ZL).

CIRCUIT DIAGRAM:


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EQUVALENT CIRCUIT:

TABULATION:

Vth Rth IL(mA)

theoretical practical theoretical practical theoretical practical

PROCEDURE:

1. Connections are made as per the circuit diagram.2. Check your connections before switch on the supply.

3. Find the Thevenins voltage (or) open circuit voltage.4. Replace voltage source by internal resistor.5. Determine the Thevenins resistance.6. Find ILby using Thevenins formula.7. Compare the observation reading to theoretical value.8. switch off the supply9. Disconnect the circuit.

RESULT:

Thus the Thevenins theorem was verified.

Theoretical: Practical:

Vth = Vth =

Rth = Rth =

IL = IL =


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VERIFICATION OF NORTONS THEOREM

AIM:

To verify Nortons theorem and to determine the current flow through

the load resistance.


Sl.No Components Range Quantity

1

2

3

4

5

RPS

Resistor

Ammeter

Bread board

Connecting wires

(0-15)V

10K,5.6K,8.2K

6K

(0-10)mA,mc

(0-5)mc,mc

------

------

1

Each 1

1

1

1

few

Nortons theorem:

Any linear active network with output terminals can be replaced by a

single current source. Isc in parallel with a single impedance Zth. Isc is the

current through the terminals of the active network when shorted. Zth is

called Thevennin`s impedance.

Current through RL= Isc Zth/( Zth+ZL)

CIRCUIT DIAGRAM:

5V 5V A

+

-(0-500)mA

10K 8K

4.7K 5.6K

10K 8K

4.7K

To find I sc

10K 8K

4.7K

To find R th

XMM1

Rth

I sc

5V

10K 8K

4.7K 5.6K

A

+

-(0-500)mA

To find IL

Norton


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A+

-

(0-500)mA

Isc thR

RL =5.6K

Norton`s Equivalent c ircuit

TABULATION:

Theoretical Practical

Isc Rth Isc Rth

PROCEDURE:

1. Connections are made as per the circuit diagram.2. Check your connections before switch on the supply.3. Find the Nortons current (or) short circuit current in load resistance.4. Replace voltage source by internal resistor.5. Determine the equivalents resistance.6. Find ILby using Nortons formula.7. Compare the observation reading to theoretical value.8. switch off the supply9. Disconnect the circuit.

RESULT:

Thus the Nortons theorem was verified.

Theoretical: Practical:Isc = Isc =

Rth = Rth =IL = IL =


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3. SUPER POSITION THEOREM

AIM:

To verify superposition theorem and determine the current following

through the load resistance.



1

2

3

4

5

RPS

Resistor

Ammeter

Bread board

Connecting wires

(0-15)V

1K,220,470

(0-1)mA,mc

(0-5)mA mc

------

------

1

Each 1

1

1

1

few

Superposition theorem

In a linear circuit containing more than one source, the current that

flows at any point or the voltage that exists between any two points is the

algebraic sum of the currents or the voltages that would have been produced

by each source taken separately with all other sources removed.

CIRCUIT DIAGRAM:

12V 10 V

220 ohm 470 ohm

1 K

10 V

220 ohm 470 ohm

1 K

A+

-(0-20)mA

12V 10 V

220 ohm 470 ohm

1 K

A+

-(0-20)mA

TO find I When 10V source is acting alone2

12V

220 ohm 470 ohm

1 K

A+

-(0-20)mA

To find I when 12V source is acting alone1

To find I when two sources are acting

TABULATION:


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V(volt) I1(mA) I2(mA) I(mA)

V

1

V

2

theoretic

al

practic

al

theoretic

al

practic

al

theoretic

al

practic

al

PROCEDURE:


2. Check your connections before switch on the supply.

3. Determine the current through the load resistance.

4. Now one of the sources is shorted and the current flowing through theresistance IL measured by ammeter.

5. Similarly, the other source is shorted and the current flowing throughthe resistance IL measured by ammeter.

6. Compare the value obtained with the sum of I1&I2 should equal to I7. Compare the observation reading to theoretical value.8. switch off the supply9. Disconnect the circuit.

RESULT:

Thus the superposition theorem was verified.

4. FREQUENCY RESPONSE OF SERIES AND PARALLEL RESONANCE

CIRCUIT


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AIM:

To obtain the resonance frequency of the given RLC series electrical

network.



1

2

3

4

5

6

7

Function generator

Resistor

Voltmeter

capacitor

Bread board

Connecting wires

Decade inductance box

0-2MHz,0-3MHZ

1K,

(0-5) V

1F

-----

------

(0-100)mH

1

1

1

1

1

Few

1

FORMULA USED:Series resonance frequency F=1/ (2 (LC))

CIRCUIT DIAGRAM:

Series resonance

1.0uF

1.0k

50 mH

Fn. gen V (0-5)V

LC

R

TABULATION:

FREQUENCY (HZ) VR(VOLT)

CIRCUIT DIAGRAM

Parallel resonance


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1.0uF1.0k 50 mHFn. gen

V (0-5)VLCR

TABULATION:

FREQUENCY (HZ) VR(VOLT)

PROCEDURE:


2. Vary the frequency of the function generator from 50 Hz to 20KHz.

3. Measure the corresponding value of voltage across the resistor Rfor series RLC circuit.

4. Repeat the same procedure for different values of frequency.5. Tabulate your observation.6. Note down the resonance frequency from the graph.

RESULT:

Thus the resonance frequency of series RLC circuit is obtained.

Practical value =

Theoretical value =

Thus the resonance frequency of Parallel RLC circuit is obtained.

Practical value =

Theoretical value =

5. VERIFICATION OF MAXIMUM POWER TRANSFER THEOREM

AIM:


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To find the value of resistance RL in which maximum power is

transferred to the load resistance.



1

2

3

4

5

6

Resistor

Ammeter

Bread board

Connecting wires

RPS

DRB

1K,2.2 K

(0-10) mA

-----

------

(0-30)V

(0-10)K

1

1

1

Few

1

1

Maximum power transfer theorem:

Maximum power transfer to the load resistor occurs when it has a value

equal to the resistance of the network looking back at it from the load

terminals.

CIRCUIT DIAGRAM:

1.0k

2.2k5V RL

A

(0-10)mA

+ -

1.0k

2.2k

Theoretical calculation

To find R th

R th

MODEL GRAPH:

TABULATION:


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Resistance (RL) Current I(mA) Power =I2RL

PROCEDURE:

1. Connections are given as per the circuit diagram.

2. By giving various values of the resistance in DRB, note the ammeter

Reading.

3. Calculate the power and plot the power Vs resistance graph.

4. Note the maximum power point corresponding resistance from the graph.

RESULT:

Thus the value of unknown resistance in which the maximum power

is transferred to the load was found.

Theoretical load resistance =

Practical load resistance =

Maximum power =

VERIFICATION OF RECIPROCITY THEOREM

AIM:


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To verify Reciprocity theorem and to determine the current flow through

the load resistance.



1

2

3

4

5

RPS

Resistor

Ammeter

Bread board

Connecting wires

(0-15)V

100,470,

820, 100

(0-30) mA,

------

------

1

Each 1

1

1

few

THEORY:

Reciprocity theorem

In a linear, bilateral network a voltage source V volt in a branch

gives rise to a current I, in another branch. If V is applied in the second

branch the current in the first branch will be I. This V/I are called transfer

impedance or resistance. On changing the voltage source from 1 to branch 2,

the current in branch 2 appears in branch 1.

CIRCUIT DIAGRAM

TABULATION:

Practical value :( circuit -I)


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V(volt) I(mA) Z=V/I

PRACTICAL VALUE :( CIRCUIT -I)

V(volt) I(mA) Z=V/I

PROCEDURE:

1. Connect the circuit as per the circuit diagram.

2. Switch on the supply and note down the corresponding ammeter readings.

3. Find ratio of input voltage to output current.

4. Interchange the position of the ammeter and power supply. Note down the

Corresponding ammeter readings

5. Verify the reciprocity theorem by equating the voltage to current ratio.

RESULT:

Thus the reciprocity theorem was verified

6. CHARACTERISTICS OF PN JUNCTION DIODE

AIM:

To plot the characteristic of PN junction diode.


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1

2

3

4

5

6

7

Diode

RPS

Resistor

Ammeter

voltmeter

Bread board

Connecting wires

IN 4001

(0-30)V

1K,

(0-50)mA

(0-500)A

(0-1)V

(0-30)V

----

------

1

1

1

1

1

1

1

1

few

FORMULA USED:

1. Forward Resistance Rf=VF/IF

2. Reverse Resistance Rr= VR/IR

CIRCUIT DIAGRAM

FORWARD BIAS:

(0-50)mA1K

RPS(0-30)V IN4001 (0-1)V

-

+

REVERSE BIAS:


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1K

RPS(0-30)V IN4001 (0-1)V

+

-

(0-500)microamps

TABULATION:

FORWARD BIAS REVERSE BIAS

Voltage(VF) Current IF (mA) Voltage (VR) Current IR(mA)

MODEL GRAPH:

PROCEDURE:

Forward bias:

1. The circuit connections are made as per the circuit diagram

2. Vary the power supply voltage such a way that readings are taken insteps of .1 V in the voltmeter.

3. Note down the corresponding ammeter readings.4. Plot the graph current Vs voltage.5. Same steps are followed by reverse bias.6. calculate dynamic resistance r=(V/I)

RESULT:

Thus the characteristic of PN junction diode was obtained.

(i)Forward resistance= (ii)Reverse resistance=

CHARACTERISTICS OF ZENER DIODE


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AIM:

To draw the V-I characteristic of Zener diode and find the parameter.



1

2

3

4

5

6

7

Zener Diode

RPS

Resistor

Ammeter

voltmeter

Bread board

Connecting wires

(0-30)V

1K,

(0-50)mA

(0-1)V

----

------

1

1

1

1

1

1

few

FORMULA USED:

1. Forward Resistance Rf=VF/IF

2. Reverse Resistance Rr= VR/IRTABULATION:


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FORWARD BIAS:

S.No Forward voltage (V) Forward current I (mA)

REVERSE BIAS:

S.No Reverse voltage (V) Reverse current I

(A)

MODEL GRAPH

PROCEDURE:

Forward bias characteristic:


2. Keep the RPS connected in a minimum value and switch ON thepower supply gradually increase voltage in step of .1V .

3. Note down the corresponding ammeter and voltmeter readings.4. Plot the forward V-I curve .5. calculate forward resistance Rf=(V/I)

Reverse bias characteristic:

1. Connect the circuit as per the circuit diagram.


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2. Keep the RPS connected in a minimum value and switch ON thepower supply.

3. Gradually increase voltage in step of .1V.4. Vary the power supply in step by 1 V.5. Note down corresponding reverse voltage and current.6. Plot the graph current Vs voltage.7. Plot the reverse V-I curve.

RESULT:

Thus the characteristic of Zener diode was studied and their characteristic

was drawn.

(i)Forward resistance=

(ii)Reverse resistance=

7. CHARACTERISTICS OF CE CONFIGURATION

AIM:

To draw input and output characteristics of BJT in CE configuration and

to determine its parameter.



1

2

3

4

5

6

7

Transistor

RPS

Resistor

Ammeter

voltmeter

Bread board

Connecting wires

Bc 547

(0-30)V

1K,

(0-50)mA

(0-500) A

(0-1)V,mc

(0-30)V,mc

----

------

1

2

2

1

1

1

1

few

FORMULA USED:


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1. Input impedance (hie) =VBE/IB at VCE constant

2. Forward current gain (hfe) = IC/IB at VCE constant

3. Output conductance (hoe) = IC/VCE at IB constant

4. Reverse voltage gain (hre) = VBE/VCE at IB constantCIRCUIT DIAGRAM:

(0-2)V

(0-500)micro amps1K

(0-30)V

(0-50)mA

- +

1K

RPS(0-30)V

RPS(0-30)V

MODEL GRAPH:

INPUT CHARACTERISTICS:

IE (mA)

VBE (V)

OUTPUT CHARACTERISTICS:

IC(mA) IE

VCB (V)

TABULATION:


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VCE= (v) VCE= (v) VCE= (v)

VBE(v) IB(A) VBE(v) IB(A) VBE(v) IB(A)


IB= (A) IB= (A) IB= (A)

VCE(v) IC(mA) VCE(v) IC(mA) VCE(v) IC(mA)

PROCEDURE:


2. To draw the input characteristics VCE is kept constant

3. Input RPS is varied and the corresponding values of IB and VBE

Voltage are noted

4. To draw the output characteristics IB is kept constant

5. output RPS is varied and the corresponding values of IC and VCE are

Noted.

6. Corresponding input and output characteristics curves are drawn.

RESULT:

Thus the static characteristics of CE mode configuration is drawn

from the output graph the h - parameter are determined.

(i)Input impedance =

(ii)Forward current gain =

(iii)Output conductance =

(iv)Reverse voltage gain =

8. STATIC CHARACTERISTICS OF CB CONFIGURATION


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AIM:

To draw input and output characteristics of BJT in CB configuration and

to determine its parameter.



1

2

3

4

5

6

7

Transistor

RPS

Resistor

Ammeter

voltmeter

Bread board

Connecting wires

BC 547

(0-30)V

1K,

(0-30)mA

(0-30) mA

(0-2) V,mc

(0-30)V,mc

(0-30)V,mc

-----

1

2

2

1

1

1

1

1

Few

FORMULAS USED:

1. Input impedance (hie) =VBE/IE at VCB constant

2. Forward current gain (hfe) = IC/IE at VCB constant

3. Output conductance (hoe) = IC/VCB at IE constant

4. Reverse voltage gain (hre) = VBE

/VCB

at IE

constant

CIRCUIT DIAGRAM:

1k 1k(0-100)mA

(0-2)V

RPS(0-30)V

(0-50)mA

(0-30)v

(0-30)v

MODEL GRAPH:


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TABULATION:


VCB= (v) VCB= (v) VCB= (v)

VBE(v) IE(mA) VBE(v) IE(mA) VBE(v) IE(mA)


IE= (mA) IE= (mA) IE= (mA)

PROCEDURE:


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2. To draw the input characteristics VCB is kept constant

3. VBE is varied and the corresponding values of IE are noted

4. To draw the output characteristics IE is kept constant

5. VCB is varied and the corresponding values of IC are noted

6. Corresponding input and output characteristics curves are drawn

RESULT:

Thus the static characteristics of transistor under the CB mode

Was determined.

(i)Input impedance (hib) =

(ii)Forward current gain (hfb) =

(iii)Output conductance (hob) =

(iv)Reverse voltage gain (hrb) =

9. CHARACTERISTICS OF UJT

AIM:

To determine the static characteristics of UJT.



1

2

3

4

5

6

7

UJT

RPS

Resistor

Ammeter

voltmeter

Bread board

Connecting wires

2N2646

(0-30)V

1K,22K

(0-50)mA

(0-10)V,mc

(0-30)V,mc

------

------

1

2

Each 1

1

1

1

1

Few

FORMULA USED:

1. Negative resistance = VBE/IE.

2. Intrinsic stand off ratio = (VP-VBE)/VB1B2.

CIRCUIT DIAGRAM:


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V1

0Vdc

V2

0Vdc

R1

1k

R2

I1

V3

V4

Q1

B2

B1

E

2N2646

(0-30)V

(0-30)V

RPS(0-30)V

RPS(0-30)V

(0-50)mA

2.2K

A

V

V

M

ODEL GRAPH:

TABULATION:

VB1B2= VB1B2=

VBE (V) IE (mA) VBE(V) IE(mA)

PROCEDURE:

1. Circuit connections are made as per the circuit diagram.

2. The voltage VB1B2 is kept constant and VBE is varied.

3. The corresponding values of IE are noted.

4. For different constant values of VB1B2 the values of VBE & IE are noted.

5. The input side RPS is varied slowly from zero and the voltmeter readings

are noted.


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6. At one point, the needle deflects back and currents starts increasing.

7. The currents must not increase beyond 25mA.

8. Graph is plotted.

9. The current must not increase beyond .25mA.

APPLICATION:

1. Square or Saw tooth wave generator.

2. over voltage detector.

3. Switching, timing phase control circuit etc.

RESULT:

Thus the parameter of UJT was determined from its characteristics.

1. negative resistance =2. intrinsic stand off ratio =

CHARATERISTICS OF SCR

AIM:

To determine the characteristics of SCR.

COMPONENTS REQUIRED


1

2

3

4

5

6

7

SCR

RPS

Resistor

Ammeter

voltmeter

Bread board

Connecting wires

2P4M

(0-30)V

1K,10K

(0-50)mA

(0-100) A

(0-30)V,mc

----

------

1

2

Each 1

1

1

1

1

Few

CIRCUIT DIAGRAM:


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MODEL GRAPH:

TABULATION:

IG= (A) IG= (A)

VAK(V) IAK(mA) VAK(V) IAK(mA)

PROCEDURE:

Iak

Vak(V)


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1. Circuit connections are made as per the circuit diagram.

2. Set the gate current IG equal to firing current vary anode to cathode

Voltage, VAKin steps of 0.5V and note down the corresponding anode

current IAK

3. VBO is the point where voltages suddenly drops & there is sudden

increase

in anode current IA.

4. Note down the current at that point called latching current.

5. Increase VAK insteps of N till its maximum.

6. Open the gate terminal & decrease the VAK.

7. Holding current is the current, flow in which the deflection in both

Voltmeter VAK & ammeter suddenly reduces to zero.

RESULT:

Thus the characteristic of SCR was determined.

Latching current =

Holding current =

VBO current =

10. CHARACTERISTICS OF JFET

AIM:

To determine the drain & transfer characteristics of given JFET & to

find its parameters.



1

2

3

4

5

6

FET

RPS

Resistor

Ammeter

Voltmeter

Bread board

Connecting wires

BFW 10

(0-30)V

1K

(0-10)mA

(0-30)V

(0-10)V

----

------

1

2

2

1

1

1

1

few

FORMULA USED:


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1. Drain resistance (rd) = VDS/ID

2. Trans conductance (gm) = ID/VGS

3. Amplification factor () =rd*gm.

CIRCUIT DIAGRAM:

TABULATION:

DRAIN CHARACTERISTICS:

VGS= VGS= VGS=

VDS(V) ID(mA) VDS(V) ID (mA) VDS(V) ID(mA)

MODEL GRAPH:

IdVgs=0v

Vgs=-1v

Vgs=-2v

Vds(v)

Drain Characteristics


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MODEL GRAPH:

TRANSFER CHARACTERISTICS:

VDS= VDS= VDS=

VGS(V) ID(mA) VGS(V) ID(mA) VGS(V) ID(mA)

PROCEDURE:



2. Set gate voltage VGS=-1, vary the drain voltage VDS instep of 1V & note

down the corresponding drain current ID.

3. Repeat the above procedure for VGS=0V,-2V.

4. Plot the graph for a constant VDS Vs ID

5. Find the drain resistance (rd) = VDS/ID



2. Set gate voltage VDS=1V, vary the gate voltage VGS in step of 1V and

note down the corresponding drain current I D

3. Repeat the above procedure for VDS=5V, 10V.

4. Plot the graph for VGS Vs ID.

5. Find the Trans conductance (gm)

gm = ID/VGS

Id

Vgs(v)

Transfer Characteristics:


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RESULT:

Thus the drain and t ransfer characteristics of JFET is drawn and the

parameters were determined.

1. Drain resistance (rd) =

2. Trans conductance (gm) =

3. Amplification factor () =...

CHARACTERISTICS OF MOSFET

AIM:

To draw the static characteristics of the given MOSFET and to find

its parameter.



1

2

3

4

5

6

7

RPS

Resistor

MOSFET

Ammeter

Voltmeter

Bread board

Connecting wires

(0-30)V

330 ,470

(0-50)mA

(0-10)V,

(0-30)V

------

------

1

Each 1

1

1

1

1

1

few


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FORMULA USED:

Drain resistance rd=VDS/ ID

Trans conductance (gm) = ID/VGS

Amplification factor (M) = rd* gm

CIRCUIT DIAGRAM

TABULATION:


VGS= VGS= VGS=

VDS(V) ID(mA) VDS(V) ID (mA) VDS(V) ID(mA)


VDS= VDS= VDS=

VGS(V) ID(mA) VGS(V) ID(mA) VGS(V) ID(mA)


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PROCEDURE:

Transfer characteristics:

1. Connections are made as per the circuit diagram.2. Set VDS some constant voltage.3. vary the input side RPS measure the corresponding VGS and ID4. measure the VGS in which ammeter shows deflection and VDS5. Plot the graph voltage against current.

Drain characteristics:

1. Set the input above the threshold voltage.

2. Vary the input side RPS and measure the corresponding VDS and

ID

3. Plot the graph voltage against current.

RESULT:

Thus the characteristics of MOSFET were drawn.

Drain resistance rd=VDS/ ID =

Trans conductance (gm)= ID/VGS =

Amplification factor (M) = rd* gm =

11. CHARACTERISTICS OF DIAC

AIM:

To draw the VI characteristics of the given DIAC and determine cut in

voltage.



1

2

3

4

5

6

7

RPS

Resistor

DIAC

Ammeter

Voltmeter

Bread board

Connecting wires

(0-60)V

1 K

DB3

(0-30)mA

(0-50)V

------

------

1

1

1

1

1

1

few


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CIRCUIT DIAGRAM

DIAC

V112 V

1.0k

V

A+ -

+

_

MT2 (+)

MT1(-)

(0-30)mA

(0-50)V(0-60)V

RPS

MT1 (-ve) with respect to MT2

V212 V

1.0k

V

A+ -

+

_

MT1 (+)

MT2(-)

(0-30)mA

(0-50)V(0-60)VRPS

MT1 (+ve) with respect to MT2

MT1 is positive with respect to MT2

Sl.NO Voltage(V) Current(mA)


Sl.NO Voltage(V) Current(mA)


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PROCEDURE:

1. MT1 is positive w.r.t MT2.2. Connections are made as per the circuit diagram.3. Vary the power supply.4. Note down the corresponding ammeter and voltmeter reading.5. Plot the graph V against I.6. MT1 is negative w.r.t. MT2.7. Repeat the step 3 to 5.

RESULT:

Thus the characteristics of DIAC were drawn and the cut in voltage was

determined.

CHARACTERISTICS OF TRIAC

AIM:

To draw the characteristics of the given TRIAC and determine break

over voltage.



1

2

3

4

5

6

7

RPS

Resistor

TRIAC

Ammeter

Voltmeter

Bread board

Connecting wires

(0-30)V

1 K/5w, 1 K

(0-50)mA

(0-15)V

(0-30)V

------

------

2

2

1

2

1

1

1

few


38/41

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THEORY:

It is a three terminal semiconductor switching device which can

control alternating current in a load. Its three terminals are MT1 and MT2

and the gate. Triac is equivalent to two SCRs connected in parallel but in the

reverse direction. So triac will act as a switch for both directions.

Like an SCR, a triac also starts conducting only when the breakover

voltage is reached. Earlier to that the leakage current which is very small in

magnitude flows through the device and therefore remains in the OFF state.

The device, when starts conducting, allows very heavy amount of current to

flow through it. The high inrush of current must be limited using external

resistance, or it may otherwise damage the device.

During the positive half cycle, MT1 is positive w.r.t MT2, whereas

MT2 is positive w.r.t MT1 during negative half cycle. A Triac is a

bidirectional device and can be triggered either by a positive or by a

negative gate signal. By applying proper signal at the gate, the breakover

voltage of the device can be changed: thus phase control process can be

achieved.

Triac is used for illumination control, temperature control, liquid

level control, motor speed control and as static switch to turn a.c power ON

and OFF.

CIRCUIT DIAGRAM

(0-30)V

RPS

A

V

A

MT2

MT11K/5W

1K/5W

(0-50)mA

(0-30)mA

(0-15)V(0-30)V

RPS

+ _+

_


(0-30)V

RPS

A

V

A

MT1

MT21K/5W

1K/5W

(0-50)mA

(0-30)mA

(0-15)V(0-30)V

RPS

+ _+

_


_ +

_ +


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TABULATION:


IG= IG=

VMT2 IMT2 VMT2 IMT2


IG= IG=

VMT2 IMT2 VMT2 IMT2

PROCEDURE:

1. Connect the circuit as per circuit diagram.2. To set gate current (Ig),VMT1,VMT23. Vary Vg till VAKsuddenly drops.4. Note down the corresponding IG,set gate current equal firing

current.

5. Vary anode to cathode Vge.6. Vary VAKsupply voltage in steps 7 note down the corresponding

ammeter readings.

7. Open the gate terminal & decrease VAK.RESULT:

Thus the characteristic of TRIAC was drawn.

MT1break over voltage (VBO) =

MT1break over current (IBO) =

MT2break over voltage (-VBO) =

MT2break over current (-IBO) =


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12.CHARACTERISTICS OF PHOTODIODE

AND PHOTOTRANSISTOR

Aim:

To study of photo-detectors characteristics.

1. Photo-diode.

2. Photo-transistor

APPARATUS REQUIRED:

S.

No.

Apparatus

Required

Range Quantity

1 Power supply (0-30) V 2

2 Ammeter (0-10) mA 1

3 Voltmeter (0-10) V

(0-30) V

1

1

4 Resistor 680

1 K

1

1

5 Breadboard - 1

6 Connecting wires - 10

7 Photo diode

Phototransistor

- 1

1

CIRCUIT DIAGRAM

PHOTO DIODE

TABULATION

PHOTO TRANSISTOR


41/41

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TABULATION

Distance(cm) Current

PROCEDURE

1) Connect the circuit as per the circuit diagram.

2) Set the voltage of the bulb (Say 2V), vary the

Voltage of the diode in stepsof 1Vand note down

The corresponding diode value Ir

3) Repeat the above Procedure for Vd=4V, 6V,etc

4) Plot the graph.

RESULT

Thus the following characteristics of Photo diode & PhotoTransistorwere obtained and graph was drawn.

ec2155 - circuits & devices lab manual

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