EC2155-Circuits and Devices lab
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Transcript of EC2155-Circuits and Devices lab
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VERIFICATION OF KIRCHHOFFS CURRENT LAW
CIRCUIT DIAGRAM
TABULATION:
S.no Supply Voltage (V) I1 (mA) I2 (mA) I3 (mA)I2 + I3
(mA)
1
2
3
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Expt.No:1
Verification of KCL and KVL
Aim:
To verify a) Kirchhoffs Current Law
b) Kirchhoffs Voltage Law
Materials Required:
S.No Components/Equipments Range Quantity
1 RPS (0-15)V 1
2 Ammeter (0-30)mA 3
3 Voltmeter (0-30)V 2
4 Resistors 5001K
3.3K
11
2
5 Bread Board 16 Connecting Wires As reqd.
Theory:
Kirchhoffs Current Law (KCL)
Kirchhoffs Current Law states that the algebraic sum of all currents at any node in a
circuit is zero.
i.e. sum of currents entering a node = sum of currents leaving the node
Procedure:
Kirchhoffs Current Law (KCL)
1. Make connections as per the circuit diagram.2. Switch on the power supply.3. Note down the ammeter readings and verify KCL.4. Repeat the experiment with different values of supply voltages.
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VERIFICATION OF KIRCHHOFFS VOLTAGE LAW
CIRCUIT DIAGRAM
TABULATION:
S.no Supply Voltage (V) V1 (V) V2 (V) V3 (V) V1 + V2 + V3
1
2
3
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Theory:
Kirchhoffs Voltage Law (KVL)
Kirchhoffs Voltage Law states that the algebraic sum of all voltages across any set of
branches in a closed loop is zero.
i.e. sum of voltage drop = sum of voltage rise
Procedure:
Kirchhoffs Voltage Law (KVL)
1. Make connections as per the circuit diagram.2. Switch on the power supply.3. Note down the voltmeter readings and verify KVL.4. Repeat the experiment with different values of supply voltages.
Result:
Thus Kirchhoffs Current and Voltage laws were verified.
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VERIFICATION OF THEVENINS THEOREM
CIRCUIT DIAGRAM
Figure 1:
Figure 2:
Figure 3:
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Expt.No:2
Verification of Thevenin and Nortons Theorem
Aim:
To verify a) Thevenins Theorem
b) Nortons Theorem
Materials Required:
S.No Components/Equipments Range Quantity
1 RPS (0-30)V 1
2 Ammeter (0-1)mA 1
3 Voltmeter (0-10)V 1
4 DRB (0-1)M 1
5 Resistors 560
1K470
10K5.6K
1
21
32
6 Bread Board 1
7 Connecting Wires As reqd.
Theory:
Thevenins Theorem
Thevenins theorem states that any two-terminal linear network having a number of
voltage, current sources and resistances can be replaced by a simple equivalent circuit consisting
of a single voltage source in series with a resistance, where the value of the voltage source is
equal to the open circuit voltage across the two terminals of the network and resistance is equalto the equivalent resistance measured between the terminals with all the energy sources replaced
by their internal resistances.
Procedure:
Thevenins Theorem
1. Connect the circuit as shown in the circuit diagram.2. Measure the voltage across the load (VL) using a voltmeter or multimeter after switching
on the power supply.
To find Thevenins Equivalent Circuit:
3. Remove the load resistance and measure the open circuited voltage VTH across the outputterminal (as in figure 2).
4. Remove the voltage source and measure the resistance RTH across the output (as in figure3) using multimeter.
5. Connect the Thevenin equivalent circuit as in figure 4.6. Measure the value of load voltage VL across the load resistance.
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Figure 4:
THEVENINS EQUIVALENT CIRCUIT
TABULATION:
S.No VS RL VL RTH VTH VL
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VERIFICATION OF NORTONS THEOREM
CIRCUIT DIAGRAM
Figure 5:
Figure 6:
Figure 7:
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Theory:
Nortons Theorem
Nortons theorem states that any two-terminal linear network with current sources,
voltage sources and resistances can be replaced by a simple equivalent circuit consisting of a
current source in parallel with a resistance. The value of the current source is the short circuit
current between the two terminals of the network and the resistance is the equivalent resistance
measured between the terminals of the network with all the energy sources replaced by their
internal resistances.
Procedure:
Nortons Theorem
1. Connect the components as shown in the given circuit. (Figure 5).2. Measure the current through the load IL using an ammeter or multimeter.
To find Nortons equivalent circuit:3. Remove the load resistance and short circuit the output terminal. Measure the current IN
through the short circuited terminals.
4. Remove the voltage source and measure the resistance across the output terminal.5. Connect the components as in the equivalent circuit where Veq = IN . RN volt.6. Measure the load current IL through the load resistorRL.7. Verify if IL = IL.
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Figure 8:
Figure 9:
NORTONS EQUIVALENT CIRCUIT
TABULATION:
S.NoVS(V)
IL
(mA)
IN
(mA)
RN
(K)Veq = IN.RN
(V)
IL(mA)
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Result:
Thus Thevenins and Nortons theorems were verified.
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VERIFICATION OF SUPERPOSITION THEOREM
CIRCUIT DIAGRAM
Figure 1:
Figure 2:
Figure 3:
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Expt.No:3
VERIFICATION OF SUPERPOSITION THEOREM
Aim:
To verify Superposition theorem.
Components Required:
S.No Components/Equipments Range Quantity
1 RPS (0-30)V 1
2 Ammeter (0-50)mA 1
3 DRB (0-1)M 1
4 Resistors 330
470
1
1
5 Bread Board 1
6 Connecting Wires As reqd.
Theory:Superposition Theorem
It states that in any linear resistive network, the voltage across or current through any
resistor or source may be calculated by adding algebraically all the individual voltages or
currents caused by separate independent sources acting alone, with all the other independent
voltage sources replaced by short circuits and all other independent current sources replaced by
open circuits. However, superposition theorem is not applicable to unbalanced bridge circuits.
The theorem is applicable only to linear circuits. The theorem cannot be used to measure power
and it is applicable only for circuits having more than one source.
Procedure:
1. Connect the circuit as in the given circuit (Figure1).2. Switch on the power supply.3. Adjust the DRB to a certain value and measure the ammeter reading, I.4. Set V2 to a certain value and short circuit the voltage source V1 as in Figure 2, and
measure the ammeter reading, I1.
5. Set V1 at a certain value and short circuit the second voltage source V2 (as in Figure 3).Measure the ammeter reading, I2.
6. Verify if I = I1 + I2.7.
Repeat the experiment for different DRB values.
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TABULATION:
S.No
DRB
value
()
I
(mA)
I1
(mA)
I2
(mA)I1 + I2(mA)
Theoretical Practical Theoretical Practical Theoretical Practical
1
2
3
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Result:
Thus Superposition theorem was verified.
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VERIFICATION OF MAXIMUM POWER TRANSFER THEOREM
CIRCUIT DIAGRAM:
TABULATION:
S.No DRB Value, R
()Current, I
(mA)
Power, P= I2R
(W)
1.
2.
3.
4.
5.
MODEL GRAPH:
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Expt.No:4
VERIFICATION OF MAXIMUM POWER TRANSFER & RECIPROCITY THEOREMS
Aim:
To verify Maximum Power transfer and Reciprocity theorems.
Components Required:
S.No Components/Equipments Range Quantity
1 RPS (0-10)V 1
2 Ammeter (0-30)mA 1
3 DRB (0-1)M 1
4 Resistors 3.3K
2.2K1K
1
11
5 Bread Board 1
6 Connecting Wires As reqd.
Maximum Power Transfer Theorem
Theory:
Maximum Power Transfer theorem states An independent voltage source in series with a
resistance RS, delivers a maximum power to that loads resistance RL for which RL = RS .
Maximum Power Transfer theorem can also be stated in terms of Thevenin equivalent
resistance of the network as A network delivers the maximum power to a load resistance RL
when RLis equal to the Thevenin equivalent resistance of the network.
Procedure:
1. Connect the circuit as shown in figure.2. Find the Thevenin equivalent resistance of the circuit.3. Adjust the DRB for different values of resistances and note down the ammeter readings.4. Calculate the power for the corresponding resistance and current readings.5. Verify if power is maximum for RL = RTH.
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VERIFICATION OF RECIPROCITY THEOREM
CIRCUIT DIAGRAM
Figure 1:
Figure 2:
TABULATION:
S.NoVoltage, V1
(V)
Current I1
(mA)V1 / I1
Voltage, V2
(V)
Current I2
(mA)V2 / I2
1.
2.
3.
4.
5.
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Reciprocity Theorem
Theory:
Reciprocity theorem states In any passive linear bilateral network, if the single voltage
source Vx in the branch x produces the current response Iy in the branch y, then the removal of
the voltage source from the branch x and its insertion in the branch y will produce the current
response Iy in the branch x.
In other words, In a linear network, if the position of the excitation and response are
interchanged, their ratio remains the same.
Procedure:
1. Connect the circuit as in figure 1.2. For different values of V1, note down the corresponding values of I1 in the ammeter.3. Calculate the values of V1/I1 and tabulate them.4. Now change the circuit as in figure 2.5.
For different values of V2, note down the corresponding values of I2 in the ammeter.
6. Calculate the values of V2/I2 and tabulate them.7. Verify if V1/I1 = V2/I2.
Result:
Thus Maximum power transfer theorem and reciprocity theorems were verified.
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SERIES RESONANCE CIRCUIT
CIRCUIT DIAGRAM:
TABULATION:
S.NoInput Frequency
(Hz)
Output Voltage
(V)
MODEL GRAPH:
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Expt.No:5
FREQUENCY RESPONSE OF SERIES AND PARALLEL RESONANCE CIRCUITS
Aim:
To find the resonant frequency of series and parallel RLC circuits.
Components Required:
S.No Components/Equipments Range Quantity
1 Function Generator (0-1)MHz 1
2 Voltmeter (0-5)V 1
3 Resistor 1K 1
4 Capacitor 1F 1
5 Inductor 50mH 1
6 Bread Board 1
7 Connecting Wires As Reqd.,
Theory:The resonance of a series RLC circuit occurs when the inductive and capacitive reactance
are equal in magnitude but cancel each other because they are 180 apart in phase. It has
minimum impedance at resonance frequency and the phase angle at resonance is equal to zero.
In parallel RLC circuits the circuit behaves purely resistive at resonance. Since inductive
and capacitive reactance currents are equal and opposite in phase, they cancel one another at
parallel resonance. If a capacitor and an inductor, each with negligible resistance are connected
in parallel and the frequency is adjusted such that the reactances are exactly equal, current will
flow through the inductor and capacitor, but the total current will be negligible. The impedance
of parallel RLC circuit is almost infinite.
Formula Used:
Resonant frequency, fr=
(Hz)
Procedure:
1. The connections are made as per the circuit diagram.2. Vary the input frequency and tabulate the corresponding voltage readings.3. Plot the graph and note down the resonant frequency from the graph.4. Verify if the resonant frequency from the graph is equal to the theoretical resonant
frequency.
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PARALLEL RESONANCE CIRCUIT
CIRCUIT DIAGRAM
TABULATION:
S.NoInput Frequency
(Hz)
Output Voltage
(V)
MODEL GRAPH:
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Result:
Thus series and parallel resonant circuits were constructed and their frequency response
curves were drawn.
Resonant frequency of series RLC circuit =
Resonant frequency of parallel RLC circuit =
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CHARACTERISTICS OF PN-JUNCTION DIODE
CIRCUIT DIAGRAM:
FORWARD BIAS:
REVERSE BIAS:
CIRCUIT SYMBOL:
MODEL GRAPH
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Expt.No:6
CHARACTERISTICS OF P-N JUNCTION DIODE AND ZENER DIODE
Aim:
To plot the V-I characteristics of the given PN junction diode and Zener diode under
forward bias and reverse bias.
Components Required:
S.No Components/Equipments Range Quantity
1 PN junction diode 1N4001 1
2 Zener diode 1
3 Ammeter (0-50)mA
(0-500)A
1
1
4 Voltmeter (0-1)V
(0-30)V
1
1
5 Resistor 1K 16 RPS (0-15)V 1
7 Connecting Wires As Reqd.,
PN Junction Diode
Theory:
If donor impurities are introduced into one side and acceptor into the other side of a
single crystal of a semiconductor, a p-n junction is formed. Initially there are only p-type carriers
to the left of the junction and only n-type carriers to the right of the junction.
Forward Bias:
The P-type of the semiconductor is connected to the positive of the battery and N-type tothe negative of the battery.
Width of the depletion region decreases with increase in the bias voltage. Hence there is gradual increase in current with increasing voltage.
Reverse Bias:
The P-type of the semiconductor is connected to the negative of the battery and N-type tothe positive of the battery.
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P-N JUNCTION DIODE
TABULATION:
FORWARD BIAS:
S.No Forward Voltage
VF (V)
Forward Current
IF (V)
REVERSE BIAS:
S.No Reverse Voltage
VR(V)
Reverse Current
IR(V)
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Width of the depletion region increases with increase in bias voltage which results in highresistance.
Hence minimum current flows through the diode.Formula Used:
Resistance = V / I (ohms)
Procedure:
1. Make connections as per the circuit diagram.2. Vary the voltage in the regulated power supply and note down the corresponding
ammeter and voltmeter readings.
3. Tabulate the readings and plot the graph with voltage in X-axis and current in Y-axis.4. Calculate the value of forward resistance.
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CHARACTERISTICS OF ZENER DIODE
CIRCUIT DIAGRAM:
FORWARD BIAS:
REVERSE BIAS:
CIRCUIT SYMBOL:
V-I CHARACTERISTICS:
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ZENER DIODE
Theory:
The zener diode uses a p-n junction in reverse bias to make use of the zener effect
(breakdown phenomenon) which holds the voltage close to a constant value called the zener
voltage. The constant reverse voltage VZ of the zener diode makes it a valuable component for
the regulation of the output voltage against both variations in the input voltage from an
unregulated power supply or variations in the load resistance.
Procedure:
1. Make connections as per the circuit diagram.2. Vary the voltage in the regulated power supply and note down the corresponding
ammeter and voltmeter readings.
3. Tabulate the readings and plot the graph with voltage in X-axis and current in Y-axis.4. Note down the value of zener voltage VZ.
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ZENER DIODE
TABULATION:
FORWARD BIAS:
S.No Forward Voltage
VF (V)
Forward Current
IF (V)
REVERSE BIAS:
S.No Reverse Voltage
VR(V)
Reverse Current
IR(V)
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CHARACTERISTICS OF CE CONFIGURATION
CIRCUIT DIAGRAM:
INPUT CHARACTERISTICS:
OUTPUT CHARACTERISTICS:
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Expt.No:7
CHARACTERISTICS OF CE CONFIGURATION
Aim:
To plot the input and output characteristics of a given BJT in CE configuration and
determine its hybrid parameters.
Components Required:
S.No Components/Equipments Range Quantity
1 Bipolar Junction Transistor BC 107 1
2 Ammeter (0-10)mA
(0-500)A
1
1
3 Voltmeter (0-5)V
(0-10)V
1
1
4 Resistor 10K 1
5 RPS (0-15)V 26 Connecting Wires As Reqd.,
Theory:
In CE configuration, the base is taken as input terminal, collector is taken as output
terminal and emitter is taken as common terminal. The input characteristics are drawn for
different values of IB and VBE with VCE constant. The output characteristics are drawn for
different values of IC and VCE with IB constant.
Procedure:
1. Make connections as per the circuit diagram.2. To obtain the input characteristics, keep the value of VCE constant. For different values of
VBE, tabulate the corresponding values of IB.
3. Repeat the procedure for various constant values of VCE.4. Plot the graph and calculate the hybrid parameters.5. To obtain the output characteristics, keep the value of IB constant. For different values of
VCE, tabulate the corresponding values of IC.
6. Repeat the procedure for various constant values of IB.7. Plot the graph and calculate the hybrid parameters.
Formula Used:
1. Input Impedance (hie) =
, VCE = constant
2. Forward Current Gain (hfe) =
, VCE = constant
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PIN DIAGRAM SYMBOL
TABULATION:
INPUT CHARACTERISTICS:
S.NoVCE = V VCE = V VCE = V
VBE (V) IB (A) VBE (V) IB (A) VBE (V) IB (A)
OUTPUT CHARACTERISTICS:
S.NoIB = A IB = A IB = A
VCE (V) IC (mA) VCE (V) IC (mA) VCE (V) IC (mA)
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3. Reverse Voltage Gain (hre) =
, IB = constant
4. Output Conductance (hoe) =
, IB = constant
Result:
Thus the input and output characteristics of the given BJT were obtained for CE
configuration.
Input Impedance (hie) =
Forward Current Gain (hfe) =
Reverse Current Gain (hre) =
Output Conductance (hoe) =
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CHARACTERISTICS OF CB CONFIGURATION
CIRCUIT DIAGRAM:
INPUT CHARACTERISTICS:
OUTPUT CHARACTERISTICS:
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Expt.No:8
CHARACTERISTICS OF CB CONFIGURATION
Aim:
To plot the input and output characteristics of a given BJT in CB configuration and
determine its hybrid parameters.
Components Required:
S.No Components/Equipments Range Quantity
1 Bipolar Junction Transistor BC 107 1
2 Ammeter (0-30)mA 2
3 Voltmeter (0-5)V
(0-25)V
1
1
4 Resistor 100 1
5 RPS (0-15)V 2
6 Connecting Wires As Reqd.,
Theory:
In CE configuration, the emitter is taken as input terminal, collector is taken as output
terminal and base is taken as common terminal. The input characteristics are drawn for different
values of IE and VBE with VCB constant. The output characteristics are drawn for different values
of IC and VCB with IE constant.
Procedure:
1. Make connections as per the circuit diagram.2. To obtain the input characteristics, keep the value of VCB constant. For different
values of VBE, tabulate the corresponding values of IE.
3. Repeat the procedure for various constant values of VCB.4. Plot the graph and calculate the hybrid parameters.5. To obtain the output characteristics, keep the value of IE constant. For different values
of VCB, tabulate the corresponding values of IC.
6. Repeat the procedure for various constant values of IE.7. Plot the graph and calculate the hybrid parameters.
Formula Used:
1. Input Impedance (hib) =
, VCB = constant
2. Forward Current Gain (hfb) =
, VCB = constant
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PIN DIAGRAM SYMBOL
TABULATION:
INPUT CHARACTERISTICS:
S.NoVCB = V VCB = V VCB = V
VEB (V) IE (mA) VEB (V) IE (mA) VEB (V) IE (mA)
OUTPUT CHARACTERISTICS:
S.NoIE = mA IE = mA IE = mA
VCB (V) IC (mA) VCB (V) IC (mA) VCB (V) IC (mA)
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CHARACTERISTICS OF UJT
CIRCUIT DIAGRAM:
CHARACTERISTIC CURVE: Symbol Pin Diagram
TABULATION:
S.No
VB1B2 = (V) VB1B2 = (V)
VB1E (V) IE (mA) VB1E (V) IE (mA)
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Expt.No.9
CHARACTERISTICS OF UJT AND SCR
Aim:
To obtain the characteristics of UJT and SCR.
Components Required:
S.No Components/Equipments Range Quantity
1 UJT 2N2646 1
2 SCR 2P4M 1
3 Resistor 1K
470
330
11
1
4 RPS (0-5)V 2
5 Ammeter (0-20)mA
(0-100)mA
1
1
6 Voltmeter (0-5)V(0-20)V
11
7 Connecting Wires As Reqd.,
UJT
Theory:
UJT is a three terminal semiconductor switching device. As it has one PN junction, it is
called Uni Junction Transistor. The heavily doped P region is called emitter E and lightly doped
n region constitute base B1 and B2. The negative resistance property of UJT enables it to be
employed in various applications namely relaxation oscillator, sawtooth generator, switching,
timing and phase control circuits.
Procedure:
1. Connect the circuit as per the circuit diagram.2. Vary the value of input voltage and note down the corresponding emitter current IE and
VBE with VB1B2 constant.
3. Plot the graph with VBE against IE.4. Calculate the intrinsic stand-off ratio using formula.
Formula Used:
1. Intrinsic Stand-off ratio, = Intrinsic stand-off ratio = (VP-VD)/VB1B22. Negative Resistance =
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CHARACTERISTICS OF SCR
CIRCUIT DIAGRAM:
CHARACTERISTICS CURVE: SYMBOL
PIN DIAGRAM
TABULATION:
Before Triggering:
IG = mA
VAK(V) IA (mA)
After Triggering:
IG = mA
VAK(V) IA (mA)
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SCR
Theory:
SCR is a four layer PNPN device. It is a rectifier with a control element. It has three
diodes connected back to back. It is widely used as a switching device in power control
applications. It has three terminals namely Anode (A), Cathode (K) and Gate (G). The gate
controls the firing of the SCR.
Procedure:
1. Connections are made as per the circuit diagram.2. Keep IG = 0mA.3. Vary the power supply and note down the anode to cathode voltage V AK and the anode
current IA.
4. Increase the gate current till the SCR gets triggered and keep IG constant.5. Now vary the power supply and note down the corresponding anode to cathode voltage
VAKand the anode current IA.6. Note down the holding current IH and break-over voltage (VBO).7. Plot the graph.
Result:
Thus the characteristics of UJT and SCR were obtained.
SCR:
Holding Current IH =
Break-over Voltage VBO =
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CHARACTERISTICS OF JFET
CIRCUIT DIAGRAM:
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Expt.No.10
CHARACTERISTICS OF JFET AND MOSFET
Aim:
To determine and plot the drain and transfer characteristics of the given JFET and
MOSFET
Components Required:
S.No Components/Equipments Range Quantity
1 JFET BFW10 1
2 MOSFET 1
3 Resistor 1K 1
4 RPS (0-10)V 1
5 Ammeter (0-15)mA
(0-50)mA
1
1
6 Voltmeter (0-3)V
(0-10)V(0-25)V
(0-30)V
1
11
1
7 Connecting Wires As Reqd.,
JFET
Theory:
FET is a semiconductor switching device in which the flow of electron in the
conducting region is controlled by an external electric field. As current conduction is only
by majority carriers, FET is said to be a unipolar device.
A Junction Field Effect Transistor (JFET) has three terminals namely source (S),
Drain (D) and Gate (G). Source S is connected to negative of the battery. Drain D isconnected to positive of the battery. A PN junction is formed which is the Gate G.
Procedure:
1. Connect the circuit as per the circuit diagram.2. To obtain drain characteristics:
i. Keep voltage VGS constant.ii. Increase the voltage VDS in a number of steps and note the corresponding
drain current ID.
iii. Repeat the procedure for various constant values of VGS.iv. Plot the graph with VDS against ID.
3. To obtain transfer characteristics:i. Keep the voltage VDS constant.
ii. Increase the voltage VGS in a number of steps and note the correspondingdrain current ID.
iii. Repeat the procedure for various constant values of VDS.iv. Plot the graph with VGS against ID for various constant values of VDS.
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TABULATION:
Drain Characteristics:
S.NoVGS = (V) VGS = (V)
VDS (V) ID (mA) VDS (V) ID (mA)
Transfer Characteristics:
S.NoVDS = (V) VDS = (V)
VGS (V) ID (mA) VGS (V) ID (mA)
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v. Determine the values of drain resistance, transconductance, amplificationfactor, pinch-off voltage and drain-source saturation current.
Formula Used:
1. Drain Resistance, rd = VDS / ID , VGS = constant2. Trans-conductance, gm = ID / VGS , VDS = constant3. Amplification factor, = rd * gm
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CHARACTERISTICS OF MOSFET
CIRCUIT DIAGRAM:
DRAIN CHARACTERISTICS TRANSFER CHARACTERISTICS
SYMBOL PIN DIAGRAM
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MOSFET
Theory:
Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) is also called Insulated
Gate Field Effect Transistor (IGFET). MOSFET can be of two types namely depletion type
MOSFET and enhancement type MOSFET. MOSFET has only one P region which is called
substrate (SS). The Gate (G) is insulated from the conducting channel by metal oxide insulating
film. When a negative bias is applied at the gate, it acts as depletion MOSFET and when a
positive bias is applied at the gate, it acts as enhancement type MOSFET.
Procedure:
1. Connect the circuit as per the circuit diagram.2. To obtain drain characteristics:
i. Keep voltage VGS constant.ii. Increase the voltage VDS in a number of steps and note the corresponding
drain current ID.iii. Repeat the procedure for various constant values of VGS.iv. Plot the graph with VDS against ID.
3. To obtain transfer characteristics:i. Keep the voltage VDS constant.
ii. Increase the voltage VGS in a number of steps and note the correspondingdrain current ID.
iii. Repeat the procedure for various constant values of VDS.iv. Plot the graph with VGS against ID for various constant values of VDS.
4. Determine the values of drain resistance, transconductance, amplification factor,pinch-off voltage and drain-source saturation current.
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TABULATION:
Drain Characteristics:
S.NoVGS = (V) VGS = (V)
VDS (V) ID (mA) VDS (V) ID (mA)
Transfer Characteristics:
S.NoVDS = (V) VDS = (V)
VGS (V) ID (mA) VGS (V) ID (mA)
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Result:
Thus the characteristics of JFET and MOSFET were obtained.
JFET:
Drain resistance, rd =
Transconductance, gm =
Amplification factor, =
Pinch-off voltage, VP =
Drain-source Saturation Current IDSS =
MOSFET:
Drain resistance, rd =
Transconductance, gm =
Amplification factor, =
Drain-source Saturation Current IDSS =
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CHARACTERISTICS OF DIAC
CIRCUIT DIAGRAM:
MT1 negative with respect to MT2 V-I CHARACTERISTICS
MT2 negative with respect to MT1 VBO
TABULATION:
MT1 positive with respect to MT2
S.NoVoltage V
(V)
Current I
(mA)
MT2 positive with respect to MT1
S.NoVoltage V
(V)
Current I
(mA)
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Expt.No:11
CHARACTERISTICS OF DIAC AND TRIAC
Aim:
To determine the characteristics of the given DIAC and TRIAC.
Components Required:
S.No Components/Equipments Range Quantity
1 DIAC DB3 1
TRIAC BT136 1
2 Resistor 1K 1
3 RPS (0-60)V 1
4 Ammeter (0-10)mA
(0-50)mA
(0-100)mA MC
1
1
1
5 Voltmeter (0-15)V
(0-100)V MC
1
1
6 Connecting Wires As Reqd.,
DIAC
Theory:
A diac is a two terminal bidirectional semiconductor device that can be switched from
OFF state to ON state for either polarity of applied voltage. When a positive or negative voltage
is applied across the terminals, a small amount of leakage current flows. As the applied voltage
is increased, the leakage current will continue to flow until the voltage reaches the break-over
voltage VBO. At this point, avalanche breakdown occurs and the device exhibits negative
resistance.
Procedure:
1. Connect the circuit as per the circuit diagram.2. MT1 is kept positive with respect to MT2.3. Vary the supply voltage and note down the corresponding voltmeter and ammeter
readings.
4. Plot the graph with V against I.5. Repeat the procedure with MT2 kept negative with respect to MT1.
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CHARACTERISTICS OF TRIAC
CIRCUIT DIAGRAM:
V-I CHARACTERISTICS:
TABULATION:
S.No
IG1= (mA) IG2 = (mA)
VAK(V) IA (mA) VAK(V) IA (mA)
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TRIAC
Theory:
A TRIAC is a three terminal semiconductor switching device which can control
alternating current in a load. It consist of 2 SCRs connected in anti-parallel, so its characteristics
in I and III quadrants are essentially identical to those of an SCR in the I quadrant. The TRIAC
can be operated with either positive or negative gate control voltage, but in normal operation
usually the gate voltage is positive in I quadrant and negative in III quadrant. The supply voltage
at which the TRIAC is turned ON depends on the gate current. The greater the gate current, the
smaller the supply voltage at which the TRIAC is turned ON.
Procedure:
1. Connect the circuit as per the circuit diagram.2. To set the gate current IG, set VMT1, VMT2 and vary VG till VAK suddenly drops. Note
down the corresponding gate current IG.
3.
Set the gate current equal to firing current and vary the anode to cathode voltage.4. Vary VAKin steps and note down the corresponding ammeter readings.5. Open the gate terminal and decrease VAK.6. Plot the graph.
Result:
Thus the characteristics of DIAC and TRIAC were determined.
DIAC: