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CIRCUITS AND DEVICES LABORATORY
1. Verification of KVL and KCL
2. Verification of Thevenin’s and Norton’s Theorems
3. Verification of superposition Theorem.
4. Verification of Maximum power transfer and reciprocity theorems.
5. Frequency response of series and parallel resonance circuits.
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.
VERIFICATION OF KVL AND KCLAim
To verify Kirchoff’s current law and voltage law theoretically and practically for given network
Apparatus required
S.no Item Range Type Qty1. DC Regulated power supply (0-30)V 12. Ammeter (0-10)mA MC 1
Ammeter (0-25)mA MC 23 Volt meter (0-10V) MC 34. Single dial decade resistance box - - 35. Connecting wires - -
Kirchoff’s current law Kirchoff’s current law (KCL) states that the algebraic sum of currents entering a node
is zero.
Kirchoff’s voltage lawKirchoff’s voltage law (KVL) states that the algebraic sum of all voltages around a
closed path (or loop) is zero.
Circuit diagram (KCL)
Tabulation
S.NoApplied
voltage inVolts
Current in mA Total currentI1= I2 + I3 in mA
(Theoretical Value)I1
I2 I3
Procedure:Current Law
1. Connections are made as per the circuit diagram2. Apply various voltages by using RPS and note down the currents I1,I2 and I3 for the
corresponding voltages3. Find the total current theoretically by using the formula I1= I2 + I3
Voltage Law1. Connections are made as per the circuit diagram2. Apply various voltages by using RPS and note down the corresponding voltages V1, V2
and V3.3. Find the total Voltage theoretically by using the formula V= V1+ V2 + V3
Circuit diagram (KVL)
Tabulation
S.No Applied voltage inVolts
Voltage in Volts Total currentV= V1+ V2 + V3V1 V2 V3
Result:
VERIFICATION OF THEVEVIN’S AND NORTON’S THEOREM
Aim To verify Thevenin’s theorem and Norton’s theorem theoretically and practically for a given circuitApparatus required
S.NO ITEM RANGE TYPE QTY
1. DC Regulated power supply (0-30)V 1
2. Ammeter (0-50)mA MC 1
3. Ammeter (0-10)mA MC 1
4. Voltmeter (0-10)V MC 1
5. Single dial decade resistance box 4
6. Connecting wires
StatementThevenin’s theorem states that a linear two-terminal circuit can be replaced by an
equivalent circuit consisting of a voltage source VTh in series with a resistor RTh.
To find IL
Circuit (i)
To find VOC
Circuit (ii)
To find ISC
Circuit (iii)
PROCEDUREa) To find IL
1) Connections are given as per the circuit (i).2) The Load current IL is noted for various values of supply voltage and tabulated.
b) To find Voc
1) Connections are modified as shown in the circuit (ii).2) The Open circuit voltage (VOC) is noted for various values of the supply voltage and tabulated.
c) To find Isc
1) Connections are modified as shown in the circuit (iii).2) The short circuit current (ISC) is noted for various values of the supply voltage and
tabulated.
3) Thevenin’s resistance is practically calculated by using the Open circuit voltage
and short circuit current.
Tabulation
S.N
Supply
Voltage
(V)
Load
current
(IL) in
mA
Short
Circuit
Current
(ISC) in mA
Open circuit
Voltage
(VOC) in
Volts
RTH=
VOC/ ISC
in Ohms
IL=
VOC/ RL+ RTH
in mA
Theoretical
value IL in mA
VERIFICATION OF NORTON’S THEOREM
Statement
Norton’s theorem states that a linear two-terminal circuit can be replaced by an
equivalent circuit consisting of a current source IN in parallel with a resistor RN.
PROCEDURE
a) To find IL
1. Connections are given as per the circuit (i)
2. The Load current IL is noted for various values of supply voltage and tabulated.
b) To find Voc
1. Connections are modified as shown in the circuit (ii)
2. The Open circuit voltage (VOC) is noted for various values of the supply voltage
and tabulated.
c) To find Isc
1. Connections are modified as shown in the circuit (iii)
2. The short circuit current (ISC) is noted for various values of the supply voltage and
tabulated.
3) Norton’s resistance is practically calculated by using the Open circuit voltage and
short circuit current.
Tabulation
S.NSupplyVoltage
(V)
Loadcurrent(IL) in mA
ShortCircuitCurrent
(ISC)in mA
Open circuit
Voltage(VOC)inVolts
RN= VOC/ ISC
in Ohms
IL=ISC .(RN/ RN +RTH)
in mA
Theoretical valueIL in mA
Result:
VERIFICATION OF SUPERPOSITION THEOREM
Aim To verify the Superposition theorem theoretically and practically for a given circuit
Apparatus Required S.No Item Type Range Qty
1. DC Regulated power supply (0-30)V 22. Ammeter MC (0-100)mA 13. Single dial decade resistance box 34. Bread board 15. Connecting wires
Statement
The theorem states that the response in any element of a linear bilateral network having two or more sources is the algebraic sum of the responses obtained by each source acting individually while all other sources are set equal to zero.
Circuit Diagram
Determination of IL when both V1 and V2 are active
Circuit (i)
Determination of IL’ by removing V2
Circuit (ii)
Determination of IL’’ by removing V1
Circuit (iii)
Tabulation
S.No
Supply Voltage
(Volts)
Current in mA
(Practical Value) Theoretical
Value
IL in mAIL IL’ IL’’V1 V2
ProcedureA) Determination of IL’ by removing V2
1. Make connections as per the circuit diagram (ii).2. Remove V2 by short circuiting the terminal.3. Apply voltage V1 by using RPS and note down the current IL’.
B) Determination of IL’’ by removing V1
1. Make connections as per the circuit diagram (iii).2. Remove V1 by short circuiting the terminal.3. Apply voltage V2 by using RPS and note down the current IL’’.
C) Determination of IL when both V1 and V2 are active1. Make connections as per the circuit diagram (i).2. Apply the voltage V1, V2 and note down the current IL
Formula UsedIL=IL’+IL’’
IL’- current through Ammeter by removing V2
IL’’- current through Ammeter by removing V1
Result
VERIFICATION OF MAXIMUM POWER TRANSFER AND RECIPROCITY THEOREMS
MAXIMUM POWER TRANSFER THEOREMAim
To verify the Maximum Power Transfer and Reciprocity theoremsApparatus Required
S.NO
ITEM RANGE TYPE QTY
1 DC Regulated power supply (0-30)V - 12 Ammeter (0-5mA), (0-100mA) MC Each13 Voltmeter (0-10V) MC 1
4 Five Dial Decade Resistance Box - - 1
TABULATION
Voltage
(volts)
Current
(mA)
Power
(watts)
Verification of Reciprocity Theorem
StatementIn a linear, bilateral, single source network, the ratio of the excitation to response is
constant when the position of excitation and response are interchanged.Procedure
1. Connections are made as per the circuit diagram I2. The voltage is applied to the circuit using RPS and the Ammeter reading is noted for circuit II
3. Repeat the same procedure for circuit IIICircuit I
Circuit II
Circuit III
Tabulation
Readings Voltage in volts
Circuit ICurrent
R=V/IΩ
Voltage in volts
Circuit II
R=V/IΩ
in mACurrent in mA
Practical Value
Theoretical Value
Result
FREQUENCY RESPONSE OF SERIES AND PARALLEL RESONANCE CIRCUITSAim
To determine the resonant frequency and bandwidth of series and parallel resonant
circuits
Apparatus Required
S.no Item Range Type Qty
1 Function Generator 3MHz 1
2 Single dial decade resistance box 1
3 Single dial decade inductance box 1
4 Single dial decade capacitance box 1
5 Voltmeter (0-10V) MI 1
6 Ammeter (0-10mA) MI 1
7 Connecting wires
THEORY
Impedance (Z) for a serial RLC circuit is a function of the resistance (R), the
inductive reactance (XL), and the capacitive reactance (XC)
z=√ R2+( X L−XC )2
Inductive reactance is a function of the inductance (L) and frequency (f) of the AC
voltage:
X L=2πfL
Capacitive reactance is a function of the capacitance (C) and frequency (f) of the AC
voltage:
XC= 12 πfC
If the sum of XL and XC is zero, then the equation for the resonant frequency in a
series RLC circuit is
ωo=1
√ LC
The resonance frequency (ωo) is the frequency at which the output is in phase with the
input or at resonance, circuit is operating at unity power factor (purely resistive circuit). The
bandwidth (β) is defined as the range of frequencies for which the peak amplitude of the
response is at least 1/√2 times the maximum peak amplitude. The quality factor (Q) of the
resonant circuit is defined as the ratio of the resonant frequency to the bandwidth. Bandwidth
of the series resonant circuit is β=ω2−ω1=RL
Quality factor
Q=ωo
β=
ωo L
R= 1
ωo CR= 1
R √ LC
Circuit Diagram
TABULATION
S.NoFrequency
InHz
Output current (Io)in mA
Gain=20log(I0/Ii)in dB
PROCEDURE
Series resonance
1. Make the connections as shown in the figure
2. Set the input current (Ii) by using function generator as 2mA
3. Increase the frequency and note down the corresponding output current (Io)
4. Find the frequency at which the output current Io is maximum (Imax)
5. Calculate 0.707 of the maximum current
6. Plot Gain (dB) Vs f on semi-log paper
Parallel resonance
1. Make the connections as shown in the figure
2. Set the input current (Vi) by using function generator as 5V
3. Increase the frequency and note down the corresponding output voltage (Vo)
4. Find the frequency at which the output Voltage Vo is maximum (Vmax)
5. Calculate 0.707 of the maximum Voltage
6. Plot Gain (dB) Vs f on semi-log paper
For a parallel circuit, impedance is:
Bandwidth of the parallel resonant circuit is defined as:
The quality of the frequency response in parallel resonant circuit is described as:
Tabulation
S.NoFrequency
InHz
Output voltage (Vo)in volts
Gain=20log(V0/Vi)in dB
Result
CHARACTERISTICS OF PN AND ZENER DIODE
A) CHARACTERISTICS OF PN JUNCTION DIODE Aim To study the forward and reverse characteristics of PN junction diode Apparatus Required
S.No Apparatus Range Type Qty1 Voltmeter (0-10)v MC 12 Ammeter (0-10) mA MC 13 Ammeter (0-30)mA MC 14 Diode - 1 N4007 15 Resistor 1k Ω,230 Ω - Each 16 RPS (0-30V) 17 Bread Board 1
Symbol
Circuit diagram:Forward characteristics
Tabular column
S.No Voltage Vf (V) Current If(mA)
Reverse characteristics
Tabular columnS.No Voltage VR (V) Current IR(µA)
Procedure:1. The connections are given on the Bread Board as per the circuit diagram.
2. Initially keep the power supply voltage at minimum position.
2. Vary the RPS voltage in steps and the corresponding forward voltage and current are noted
3. Repeat the same process for reverse bias characteristics and note down the reverse voltage
and current.
4. Tabulate the readings and draw the forward and reverse V-I characteristics.
Theory:
A diode is an electrical device allowing the current to flow in only one direction
(forward bias) then in the other direction (reverse bias).An ideal diode will act as a unilateral
switch. An ideal diode is the perfect conductor in forward bias and perfect resistor in reverse
bias.
Forward bias:
When an external voltage applied with P-side (+ve) and N-side (-ve) is sufficient to
overcome the barrier potential, electrons and holes cross the junction and recombine. For
every recombination of an electron and a hole, one electron enters the N-side from negative
terminal of battery and one electron from an electron pair bond breaks up the bond to enter
the positive terminal, creating a hole. Thus, current flow is due to flow of electrons in the
outside circuit, flow of holes, in P-type material and flow of electrons in the N-type material.
In the forward biased condition, there is always a minimum voltage that must be
exceeded before there is sufficient conduction of current through the diode. This is known as
the cut-in voltage and is .6V for silicon and 0.2V for germanium diodes. For all forward
voltages greater than the cut-in voltage, there is a sharp rise in forward current i.e. a small
change in forward voltage causes a very large change in forward current.
Reverse bias:
When an external voltage applied with P-type material negative, the electrons which
are originally repelled away from the junction, due to negatively charged atom on Pside, are
repelled further due to attraction force between positive voltage and electrons. Thus electrons
as well as holes move further away from junction, further reducing the possibility of any
conduction this termed as reverse bias.
In the reverse biased condition, the current that flows through the diode is the reverse
leakage current. It may be few nanoampers in case of silicon diodes and typically 1µA for
germanium diodes. As the reverse biased is increased further, a point comes where the
junction breaks down and there is a steep rise in current which ultimately culminates in
device gets damaged. The reverse bias voltage which the break down occurs is known as
Peak inverse voltage of the diode.
B) CHARACTERISTICS OF ZENER DIODE
Aim: To study the forward and reverse characteristics of ZENER diode
Apparatus Required
S.No Apparatus Range Type Quantity1 Voltmeter (0-10)V MC 12 Voltmeter (0-1)V MC 13 Ammeter (0-30)mA MC 14 D.C Ammeter (0-10)mA MC 25 ZENER Diode IZ 5.3 16 Resistor 1k Ω,270 Ω Each 17 RPS (0-30V) 18 Bread board 1
Symbol:
Forward characteristics of ZENER diode
Tabular column S.No Voltage Vf(V) Current If(mA)
Reverse characteristics of ZENER diode
Tabular columnS.No Voltage VR (V) Current IR(µA)
Procedure:
1. The connections are given as per the circuit diagram in the bread board.
2. Vary the RPS voltage in steps and the corresponding forward voltage and current are noted
3. Repeat the same process for reverse bias characteristics and note down the reverse voltage
and current.
4. Tabulate the readings and draw the V-I characteristics
Theory:
A P-N junction diode which is capable of sustaining a heavy current of the zener
breakdown region is called a zener diode. Zener diodes are operated in the reverse biased
region.
Zener breakdown:
When the reverse voltage across P-N diode is increased, a stage comes when valence
electrons break up their covalent bonds and reach the conduction band to constitute current
resulting in a sudden increase in current. This is called zener breakdown
Characteristics of zener diode:
From the characteristics, when the diode is operated in the reverse region, at a certain
voltage the current increases all of sudden. This voltage is called the zener breakdown. In
zener diode as the current increases, its resistance decreases keeping almost a constant
voltage across the terminals.
Result:
CHARACTERISTICS OF BJT (COMMON EMITTER CONFIGURATION)
Aim:
To study the Input and Output characteristics of Transistor in Common Emitter
Configuration
Apparatus Required
S.No Apparatus Range Type Qty1 voltmeter (0-10)v MC 12 voltmeter (0-1)v 13 Ammeter (0-100)µ A MC 14 Ammeter (0-10)mA MC 15 Transistor BC547 16 Resistor 1k Ω,470Ω 17 RPS (0-30V) 28 Bread board9 Connecting wires
Symbol
N-P-N transistor P-N-P transistor
Circuit diagram
Model graph
Input characteristics Output characteristics
Tabular columnInput characteristics
S.NO VCE= VCE= VCE=
VBE (v) IB (µA) VBE(v) IB (µA) VBE(v) IB (µA)1Output Characteristics
S.No IB= IB= IB=
VCE (v) IC (mA) VCE (V) IC (mA) VCE= IC (mA)1
Procedure:
1. The connections are given as per the circuit diagram.
2. To obtain the input characteristics kept the VCE constant and vary VBE in steps and note
the corresponding IB value.
3. To obtain the output characteristics kept the IB constant and vary VCE in steps and note
the corresponding IC value.
4. Draw the input, output characteristics and determine the parameters from graph.
Theory:
Transistor is a solid state device that is formed when two P-N diodes are tied together.
When a thin P-type material is sandwiched between two thick N-type materials formed N-P-
N transistor. When a thin N-type material is sandwiched between two thick P-type materials
formed N-P-N transistor.
Result:
CHARACTERISTICS OF BJT (COMMON BASE CONFIGURATION)
Aim: To study the Input and Out put characteristics Transistor in Common Emitter Configuration
Apparatus Required
S.No Apparatus Range Type Qty1 voltmeter (0-10)V MC 12 voltmeter (0-1)V MC 13 Ammeter (0-20)mA MC 14 Ammeter (0-10)mA MC 15 Transistor BC 547 16 Resistor 1kΩ 27 Dual RPS (0-30V) 18 Bread board9 Connecting wires
Circuit diagram:
Procedure:
1. The connections are given as per the circuit diagram.
2. To obtain the input characteristics kept the VCB constant and vary VBE in steps and note
the corresponding IE value.
3. To obtain the output characteristics kept the IE constant and vary VCB in steps and note
the corresponding IC value.
4. Draw the input, output characteristics and determine the parameters from graph.
Tabular column
Input Characteristics
S.NO VCB= VCB= VCB=
VBE (v) IE (mA) VBE(v) IE (mA) VBE(v) IE (mA)1
Output Characteristics
S.No IE= IE= IE=
VCB (v) IC (mA) VCB (V) IC (mA) VCB= IC (mA)1
Result:
CHARACTERISTICS OF UJT AND SCR
A) CHARACTERISTICS OF UJT
Aim:
To study the characteristics of UJT (Uni Junction Transistor)
Apparatus Required
S.No Apparatus Range Quantity1 Voltmeter (0-15)V 22 Voltmeter (0-2)V 13 Ammeter (0-20)mA 14 UJT Kit 1
Circuit Diagram:
Model graph
Procedure:
1. The connections are given as per the circuit diagram 2. By varying the potentiometer set different VB1B2 voltages.
3. Vary the Input bias voltage VEB1 and note down corresponding current IE at constant VB1B2
voltage.
4. By increasing VEB1 , the emitter current will increase considerably and the VEB1 will drop
down to the valley point. For further increase in the VEB1, the emitter current will further
increase.
5. repeat the step 4 for values of VB1B2( )
Tabulate the readings and plot the graph between VEB1 and IE.
Tabular Column
S.No VB1B2= in volts VB1B2= in volts
VEB1 in volts
IE (mA) VEB1 in volts
IE (mA)
B) CHARACTERISTICS OF SCR
Aim To obtain the characteristics of Silicon Controlled Rectifier (SCR)
Apparatus RequiredS.No Apparatus Range Type Qty
1 Voltmeter (0-50)V MC 12 Voltmeter (0-15)V MC 13 Ammeter (0-50) mA MC 14 Ammeter (0-15)mA MC 15 SCR Kit 1
Circuit Diagram
Procedure:
1. Connections are given as per the circuit diagram
2. Keep the gate current (9mA) constant by varying the Potentiometer.
3. Vary the anode-cathode voltage (VAK) from Zero Volts and note down the corresponding
anode current ( IA).
4. SCR reaches its breakdown voltage and gets turned on. For further increase in the anode-
cathode voltage VAK remains the same
5. Tabulate the VAK and IA readings and plot the graph.
Model graph
Tabular column
S.NoIG= mA
VAK(V) IA(mA)
Result:
CHARACTERISTICS OF JFET AND MOSFET
A) CHARACTERISTICS OF JFET
Aim:
To study the characteristics of Field Effect Transistor (FET)
Apparatus Required
S.No Apparatus Range Type Quantity1 Voltmeter (0-1)V MC 12 Voltmeter (0-30)V MC 13 Ammeter (0-5)mA MC 14 JFET Kit 15 Patch chords
Symbol:
Theory:FET is a solid state unipolar device. Here the current is contributed by majority carriers only.
CIRCUIT DIAGRAM
Procedure:
1. The connections are given as per the circuit diagram
2. To obtain the drain characteristics keep the VGS constant and vary VDS in steps and note
down the corresponding ID value.
3. Repeat the above procedure for various VGS (0V to 1V) voltages and tabulate the
readings.
4. Plot the graph between VDS and ID for various VGS.
Model graph (output characteristics)
Tabular Column
S.NO VGS1 = (V) VGS2 = (V) VGS3 = (V)VDS (v) ID (mA) VDS (v) ID (mA) VDS (v) ID (mA)
B) CHARACTERISTICS OF MOSFETAim:
To study the characteristics of Metal Oxide Semiconductor Field Effect Transistor (MOSFET)
Apparatus Required
Apparatus Range Type QtyVoltmeter (0-5)V MC 1Voltmeter (0-15)V MC 1Ammeter (0-500)mA MC 1MOSFET Kit 1
CIRCUIR DIAGRAM
MODEL GRAPH
Drain characteristics Transfer characteristics
Procedure:
1. The connections are given as per the circuit diagram in the Bread board.
2. Initially keep the gate to source (VGS) constant at a particular voltage and vary VDS in steps
and note down the corresponding ID value.
4. Repeat the same step for various VGS (3.5Vto4.1V) voltage and tabulate the readings.
5. Plot the graph VDS versus ID for different VGS values gives the Drain characteristics.
6. For Transfer characteristics keep VDS (5V) as constant and vary VGS in steps and note
down the corresponding ID.
7. Plot the graph VGS versus ID for different VDS values gives the Transfer characteristics.
TABULAR COLUMN
Drain characteristics
S.NoVGS = V VGS = VGS = V
VDS (V) ID (mA) VDS (V) ID (mA) VDS (V) ID (mA)
Transfer characteristics
S.No VDS = V
VGS (V) ID (mA)
Result:
CHARACTERISTICS OF DIAC AND TRIACAimTo study the Forward and Reverse characteristics of DIAC and TRIAC
Apparatus Required
Apparatus Range Type QtyVoltmeter (0-50)V MC 1Voltmeter (0-15)V MC 1Ammeter (0-10)Ma MC 1Ammeter (0-25)mA MC 1
DIAC and TRIAC
Circuit DiagramDIAC Characteristics
Procedure:1. Connections are given as per the circuit diagram 2. Vary the VMT2-MT1 voltage and note down the corresponding IMT2.When break over voltage is reached, VMT2-MT1 voltage will drop abruptly and IMT2 will shoot up.3. Tabulate the readings and plot the graph between VMT2-MT1 and IMT2.
4. For reverse bias, Inter change the polarities of supply and meters in the circuit.5. Repeat the steps 2 & 3.
TRIAC Characteristics
Procedure:1. Connections are given as per the circuit diagram2. Vary the Input bias voltage Vs to 100 Volts across the MT1 and MT2 .3. The current reading is zero to the condition since the TRIAC is switched to ON state.4. To turn on the TRIAC, set the gate current 1 mA by varying the potentiometer VGMT25. Once the TRIAC is switched on, the voltage drop Vs comes down nearly (30 Volts)6. Now the TRIAC is ON condition and current start flow through the devices.7. Now increase the Vs and tabulate values Vs and IMT2. The current Is increase according to Vs8. Plot the graph between Vs and Is.
TABULAR COLUMN
S.NoVB1B2
VB1B2 IMT2 (mA) VB1B2 IMT2 (mA)1
Result:Thus the characteristics curves of DIAC and TRAIC are drawn.
CHARACTERISTICS OF PHOTO DIODE AND PHOTO TRANSISTOR
Aim
To study the characteristics of Photo diode and photo transistor
Apparatus Required
Apparatus Range Type Qtyvoltmeter (0-10)V MC 2voltmeter (0-5)V MC 1Ammeter (0-150)mA MC 1Ammeter (0-20)mA MC 1Ammeter (0-10)mA MC 1
Photodiode Kit 1Phototransistor Kit
Circuit diagramPhotodiode Characteristics
Procedure:Forward Biased Condition
1. Connections are given as per the circuit diagram.2. Initially keep the Vs potentiometer to zero position.3. Keep the switch in Forward Condition to conduct the Forward Characteristics.4. Apply input voltage 5 V6. Varying the voltage (VF) across photo diode in steps, the corresponding current (IF) is noted7. Keep the Toggle switch in reverse direction.8. Set the voltage (Vs) constant and Vary the voltage (VR) across photo diode in steps, the corresponding current (IR) is noted 9. Repeat the above step for different values of Vs (1V to 3V)
10. Plot the graph between VF/IF and VR/IR for the Vs voltage 2 V and 4 VoltsCircuit diagram:PHOTOTRANSISTOR Characteristics
Model Graph:
Procedure:1. Connections are given as per the circuit diagram.2. Initially keep the Vs potentiometer to zero position 3. Set the Vs 4. Vary the VCE and note down the corresponding IC
4. Repeat the step 4 for different values of VS (1V to3V).5. Plot the graph between VCE and IC.
Resut:
