Download Experiment No

EXPERIMENT#1 :
Objective:
To design a Common Emitter Amplifier using voltage divider network
and verifying all the parameters of the circuit
Apparatus:
DC power supply
Oscilloscope
Function Generator
Multi-meter
Project Board
Transistors NPN
Resistors
01
01
01
01
01
01
04
Circuit Diagram:
Procedure:
Design common emitter amplifier according the formulae given below
Vcc=+ 12V, VE=Vcc/2, VcEo=Vcc/2, Ico= 4mA, VB= [R2/(R1+R2)] * Vcc,
VB=VE+VBE,VE+VBE=[R2/(R1+R2)] * Vcc
Draw the circuit diagram as shown in the figure above and design the values of
the resistors according to the formulae given below
R1=R2[(V cc/(V E+VBE))-1
R2=BMIN * RE/1 0
RE=VE/lcQ
Rc=(Y cc- V EQ-V E)/lcQ
Get the resistors of the designed values and connect the components according
to the circuit. Record your observations in the following table.
Observations:
Parameters
Observed Values
Calculated Values
VBE
VcE
VR1
VR1
VRC
VRE
Conclusion:-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
EXPERIMENT#2:
Objective:
To determine the I/O impedance and gain of small signal CE amplifier
Apparatus:
DC power supply
Oscilloscope
Function Generator
Multi-meter
Project Board
Transistors NPN
Resistors
Capacitor
01
01
01
01
01
01
05
01
Circuit Diagram:
Procedure:
To find the Av, Ai, Zout and Zin the formulae will be used
Av= -Rc/re, Av = Vo/Vin, Ai=β, Ai= io/ I in, Zin= β re, Zout=Rc
Connect the circuit components as shown in the circuit diagram. The amplifier
used here is the one designed in experiment no.1
For lin: Attach a variable resistor in series with the source. Apply 5V p-p input,
vary the variable resistor until the voltage across the resistor remain half of the
source voltage.
For Zout: Apply the source voltage at collector and attach a variable resistor in
series with source. Apply the out put source voltage. Vary the resistor until the
voltage drop across it is half of the source voltage.
Record your observations in the table.
Av observed: Av=Vopp/ Vinpp
Ai observed: Ai=io.hin
EXPERIMENT#3:
Objective:
To design the input (Cin),output (Cout) and bypass (CE)
Capacitors for small signal amplifier
Apparatus:
DC power supply
Oscilloscope
Function Generator
Multi-meter
Project Board
Transistors NPN
Resistors
Capacitor
01
01
01
01
01
01
05
03
Circuit Diagram:
Procedure:
The capacitors design will be based upon the following formulae
Cin=1/[2*π*fci(Zin)]
Cout=1/[2* π *f2(Zout+ Rc)]
CE=1/[2*TT* fC3 ( RE II rei)]
rei
= R1//R2/β+ re
Design the amplifier circuit and calculate lin, lout and r/ Put these values in the
capacitors formulae and design the capacitors.
For CE fc is 10% less then Ci
For iCo fc is 10% less than CE
fC1=500
Connect the components according to the circuit diagram. Observe the input
output and gain of the amplifier with designed input output and bypass capacitors
in the circuit.
EXPERIMENT#4:
Objective:
To observe the frequency response of small signal CE amplifier
Apparatus:
DC power supply
Oscilloscope
Function Generator
Multi-meter
Project Board
Transistors NPN
Resistors
Capacitor
01
01
01
01
01
01
05
03
Circuit Diagram:
Procedure:
Connect the circuit components as show in the circuit diagram. The frequency of
amplifier using input, output and bypass capacitors is
Fcin=1/[2*TT (RS+Zin)Cin], fCE=1/[2*TT(r el II RE) CE], fcout=1/[2*TT(RL +Zo)Co
Calculate the voltage gain of the circuit by
Av=VO/Vin
Apply the different frequency ranges on amplifier and get the value of gain. Plot
the graph between Av and the frequency. Record your observations in the table.
EXPERIMENT# 05:
Objective:
To observe the operation of capacitor coupled inverter off circuit
Apparatus:
DC power supply
Oscilloscope
Function Generator
Multi-meter
Project Board
Transistors NPN
Resistors
Capacitor
01
01
01
01
01
01
03
01
Circuit Diagram:
Procedure:
Implement the circuit on the bread board. Give a unipolar signal of +5V peak at
the input. The pulse time is controlled by the capacitor value. Calculate the time
of pulse from 1 to O.The value of capacitor can be calculated using the equation
below.
I C=Ie-liT where ΐ=RC
The circuit work as an inverter. Record your observations in the table.
EXPERIMENT#6:
Objective:
To design the direct coupled BJT inverter
Apparatus:
DC power supply
Oscilloscope
Function Generator
Multi-meter
Project Board
Transistors NPN
Resistors
Capacitor
01
01
01
01
01
01
02
01
Circuit Diagram:
Procedure:
Make the circuit on the bread board according to the circuit diagram. Give a
signal of +-3V at the input. When. the input is OV then the output is high. When the
input is +5v, the output is low. Use the following formulae for the inverter design
Vi=:±3v, Ic=1mA, β min=70
Rc= (V cc- V CE)/I C
IB=lc / β min
tre=1/2f
C= tle/2.3*RB
RB=(Vin-VBE)/IB
Record your observations in tho table.
EXPERIMENT#7:
Objective:
To observe the capacitor coupled (normally on) Inverter circuit
Apparatus:
DC power supply
Oscilloscope
Function Generator
Multi-meter
Project Board
Transistors NPN
Resistors
Capacitor
01
01
01
01
01
01
02
01
Circuit Diagram:
Procedure:
' ~.
Connect the circuit components according to the circuit diagram. Design RB and
Rc. The capacitor is designed according to the following formulae
Q=CV
l*t=C*V
C= I*t/V
The circuit is normally on. It is active low circuit. When the input is high the output
is low. When the input is low the output is high. Record your observations in the
table.
Experiment # 8:
Objective:
1. To construct a dc load-line in a common-emitter amplifier
and to verify the predicted operating conditions of the
amplifier.
2. To show how the dc operating point can be determined
graphically on the output characteristics of device.
Materials Required:
DC power supply
01
. Digital- multi meter
01
04
. Resistors:
. Transistor
. Potentiometer 1 k
. ON/ Off Switch
. Bread Board
/
Circuit Diagram:
.., ,.."..,_.........
01
01
01
01
Procedure:
1. Draw the collector characteristics of the transistor 2N3055 and the load
line for common-emitter amplifier of Fig. 1. In this circuit RL = 2.2 k
and collector supply voltage Vcc = 10V. Show your computations for the
load line end points.
2. Find the intersection of the load line and the 20 uA base current curve.
Identify this point on the load line a~ Q1, operating point 1, and record in
table 1 the Ic and VCE coordinates of Q1.
3. From the load line determine and record the values o~Ie & VCE when (a) 16
= 10 uA, (b) 1B'=30 uA; (c) IB= 40 uA. Identify as Q2 the intersection of the
load line and the 40 uA base-current curve.
4. Connect the circuit of Fig. 1. Switch S1 is open, and R1is set for minimum
resistance. Close S1. Set R1 so that the base current measures 10 uA.
Record this base current value in column "IB" under the heading "Load line
value, Measured". Measure & record Ic, VCE and VEB .Repeat for each IB in
Table 1.
5. Using the measured values compute the collector current gain of transistor
operating at Q1 & Q2. Record the data in Observations. Compute also the
voltage gain and record the results in the" Table 2.
6. Connect the circuit of Fig. 2. With an EVM, monitor the VCE. Increase the
base current (by increasing VBB) slowly until the collector-to emitter
voltage stabilizes to its lowest value. Measure and record the base current
required saturating the transistor. What IS the graphical value of saturation
current?
7. Now short the base and emitter of transistor and note that a base bias
current of zero has been simulated by allowing the base to be returned to
ground. Connect the circuit & measure the voltage VCE. Does the
measured value agree with the graphical " condition of cutoff?
OBSERVATIONS:
1. Axis intercepts for the load line
lc=O, VcE=Vcc=
VcE= 0, Ic= Vcc /RL=
Table 1: Load Line Measurements
Experiment #09:
Objective:
1. To observe the effects of temperature on the operating
point of a transistor amplifier circuit
2. to show that operating point can be made independent of
temperature changes with external circuit compensation.
Materials Required: .
. Transistor 2N3055
. dc power supply
01
01
. Electron voltmeter
. Oscilloscope
. Audio signal generator
. Soldering iron
. Capacitors: 100 uF,
. Capacitors: 10 uF
01
. Resistors:100ohm,1k, 120k
. Resistor variable 100 k
01 each
. Bread Board
Circuit Diagram:
Procedure:
01
01
01
02
01
01
01
1. Connected the CE circuit of Fig. 1 with no RE connected. Adjust Rs for a
bias such that VCE will equal half of Vcc. Apply a 1 KHz signal at the input.
Adjust the amplitude of input sine wave for maximum undistorted output.
With an oscilloscope measure Vin and Vout. Calculate the gain
=VoutNin of
the stage. While observing the output, bring a hot soldering iron close to,
but not against the transistor. Record which peak, positive or negative, of
the output wave begins to distort.
2. Now insert a 100 ohm swamping resistor in the emitter leg of circuit. Once
...again readjust the base circuit resistance Rs for a VCE equal to
approximately half of Vee. Apply a maximum signal at the input such that
the output is not distorted. Record the voltage gain of the stage. While
observing the output, bring a hot soldering iron close to the transistor
Note the change, if any, on the output wave-shape.
3. Connect a 100 uF capacitor across the swamping resistor. Recheck the dc
output. VeE should be approximately half of Vee, apply a 1 KHz signal at
the input and measure the maximum undistorted output with the
oscilloscope. Record the voltage gain of the stage. Bring a soldering iron
close to the transistor and observe the effects on the output wave shape.
4. Add a resistor R2between the base and the ground of transistor in Fig 1.
Once again readjust R2 such that the output dc voltage is approximately
half of Vcc- Record the voltage gain of the stage. How do temperature
changes influence the output wave shape?
OBSERVATIONS:
1. R2=-----------------VCE = ------------------------
R1= ------------------------Vcc= --------------------------------
Av = ---------------------Which peak begins to distort?
2
VCE= ------------------
Vcc = -----------------------------
Av= ----------------------What is the change on the output wave shape?
3. VCE = --------------------
Vcc= ---------------------------
Av= --------------------Influence of temperature on output wave shape?
Experiment No.10
Objective
To observe the effect of an emitter by-pass capacitor on
amplifier gain.
Materials Reguired: .
. Transistor 2N3055
. dc power supply
01
01
. Electron voltmeter
. Oscilloscope
. Audio signal generator
. Soldering iron
. Capacitors: 100 uF,
. Capacitors: 10 uF
01
. Resistors:100ohm,1k, 120k
. Resistor variable 100 k
01 each
. Bread Board
01
Circuit Diagram:
01
01
01
02
01
01
Procedure:
. Connected the CE circuit of Fig. 1 with no RE connected. Adjust Rs for a
bias such that VCE will equal half of Vcc. Apply a 1 KHz signal at the input.
Adjust the amplitude of input sine wave for maximum undistorted output.
. Connect a 100 uF capacitor across the swamping resistor. Recheck the dc
output. VcE should be approximately half of Vcc, apply a 1 KHz signal at
the input and measure the maximum undistorted output with the
oscilloscope. Record the voltage gain of the stage. Bring a soldering iron
close to the transistor and observe the effects on the output wave shape.
. Add a resistor R2between the base and the ground of transistor in Fig 1.
Once again readjust R2 such that the output dc voltage is approximately
half of Vcc- Record the voltage gain of the stage.
OBSERVATIONS:
1. R2=-----------------VCE = ------------------------
Av = ----------------------
R1= ------------------------Vcc= --------------------------------
Experiment No.11
Objective:
1. To measure voltage gain of a CB amplifier, and to
determine the range of its linear operation.
2. "To measure the input and output impedance of the
amplifier.
3. To determine the power gain.
4. To observe the phase relationship between the input and
output signal voltages.
Materials Required:
. Transistor 2N3055
.DC power supply
. Oscilloscope
. Electron voltmeter
01
. signal generator
. Capacitor 25 uF
01
01
Resistors 500, 1k, 2.2k ohm
01 each
. Potentiometer 100 k
01
. Bread Board
01
1.
Circuit Diagram:
01
01
01
Procedure: .
1. Connect the circuit of Fig 1. Adjust Vcc to 15 volts. Monitor VCB with an
EVM. Slowly increase VEE until the voltage VCB= 7.5 volt.
2. The audio signal generators are set for minimum output at 1 KHz.
Increase the input slowly and monitor V out with an oscilloscope. Measure
the peak-to-peak value of the maximum undistorted output. Use the
oscilloscope to measure the input from the emitter to ground., Calculate
the voltage gain of the stage, Record the input and output waveforms.
3. Reduce the output of the signal generator to the lowest amplitude,
undistorted output waveform on the oscilloscope, Measure the input and
output voltages at this setting. Record the results in the observations.
4. Modify the circuit of Fig, 1 by adding a 500 ohm resistor Rx as in series
with capacitor C1. Adjust the audio generator for maximum undistorted
output as observed on oscilloscope connected across the output.
5, With an oscilloscope measure and record the peak-to-peak voltage (a) VAC
across AC, (b) VBc across BC, and (c) V out in the output. Compute Vx
across Rx by subtracting VBc from VAC. Compute and record hn and Rin.
Show your computation,
6. Do not vary the input-signal level. Connect a 100 k potentiometer in
Fig 1 in series with capacitor C2. Adjust Rout until the measured output
signal Vo equals one half of the measured in step 5c. Remove R out from
the circuit. Measure and record its resistance. This is the value of the
output impedance R out of the amplifier. Compute and record the power (in
dB) of the circuit under load. Show your computations.
Results:
.....................................................................................
. " ...... ................................
. ... ...................................
Conclusion:
..........................................................................................
..........................................................................................
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------------------------
(Lab assistant)
(Concerned Teacher)
Experiment No.12
Objective:
1. To measure the input and output impedance of a common collector
amplifier.
2. to measure its power gain.
3. To observe the phase relationship between the input and
output signal voltages.
Materials Required:
DC power supply
Transistor 2N3055
Oscilloscope
01
01
Electron Voltmeter
signal generator
01
01
Resistors: 2.2, 12, 100 K
Capacitor 25 uF
Potentiometer: 500 Ohm, 500 K
01 each
01
01 each
01
,..'
On/off switches
Bread Board
Circuit Diagram:
02
01
Procedure:
1. Connect the circuitof Fig 1, Adjust RBto a value that will produce a VE of 6
volts, Switch S1 is closed S2 open, Set AF signal generator at 1 KHz.
Connect the oscilloscope at the output terminals of the amplifier. Slowly
increase the input. Measure the peak-to-peak value of the maximum
undistorted V out, Measure and record the Input signal voltage Vin(points
AC), Compute and record the voltage gain, Record the input and output
waveforms in proper time phase,
2, Open switch 81, Increase AF generator output until Vin is at same level as
in step 1, With the oscilloscope measure and record the signal voltage VAS
across points AB. Compute the input base signal in by substituting VAB in
the formula:
lin
= VAB/RAB
And record IIN in .the observations,
3. Compute the input resistance Rin substituting Iin and Vin the formula:
Rin
=Vin/lin
Compute also the input power i2Rin,Record the results in observations.
4. Close switch S1. Reduce generator output level and with S2 open,
measure the maximum undistorted output voltage Vout.
5. Close S2. The load resistor RL is now in the circuit. Adjust RL until the
output voltage with load is one half the value of Vout measured in step 4.
Open S2. Measure & record the resistance of RL. This is the value of
output impedance R out of the circuit. Compute also the output power
V2out/Rout. Record this in observations.
6. Compute and record power gain using the formula
Ap
=Pout/Pin
Results:
.....................................................................................................................
.....................................................................................................................
Conclusion:
..........................................................................................
..........................................................................................
..........................................................................................
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------------------------
J
(Lab assistant)
(Concerned Teacher)
Experiment No.13
Objective:
1. To determine and plot the family of drain characteristics of
a JFET.
2. To determine and plot a JFET transfer curve, 1D versus VGs
for a specified value of Vds.
3. To calculate JFET parameters
Materials Required:
. dc power supply (variable)
Junction Field Effect Transistor
Electron voltmeter
Vom
.
. Bread Board
Circuit Diagram:
01
01
01
01
01
Procedure:
1. Draw a schematic of the type (N or P) of the JFET used in this experiment.
Draw the symbol of the device. Identify the drain, source and the gate. List
the maximum drain source voltage, drain current and power dissipation
from the manufacturer's manual.
2. Connect the circuit of Fig 1. Adjust VGs to zero. Record the drain-source
Voltage and drain current in table 1. Increase VGs to each of the values
shown in table and record ID for each VDs.
3. On a graph paper draw the family of drain characteristics using the data in
table 1. Vds is the horizontal axis, Id the vertical. Identify each
characteristic curve by its VGs value. Identify Vp. .
4. From the data in table 1 enter in table 2 the value of to corresponding to
each value of VGs and Vds = 15 volts.'
5. To calculate the dynamic resistance' of the device takes 2 points on the
straight part of the output curve for a VGs..of 1.5 volt. From these points
draw horizontal and vertical lines. The difference between the points at
which the horizontal lines meet the Id axis is ۵ Id. The difference between
the points at which the vertical lines meet the Vds axis is ~Vds. The
dynamic resistance rds is determined by substituting these values in the
equation.
rds = ~Vds/^Id
Experiment No.14
Objective:
1. To study the factors influencing the Voltage gain of a field
effect Transistor amplifier.
2~ To show the effects of feedback in a common source
configuration.
3. To compare the voltage gains of three circuit
configurations: common source, common drain and
common gate.
Materials Required:
. DC power supply
. JFET type
01
. Dual trace Oscilloscope
01
. Audio signal generator
. Resistors 220, 1K & 1M ohm
. Capacitors: Three 1 uF
. Bread Board
01
01
01 each
01
01
Circuit Diagram:
Procedure:
1. Connect the circuit of Fig 1 (a) Apply a 5 KHz sine wave signal at the input
and adjust the input signal level Vin for maximum undistorted output. With
an oscilloscope measure peak-to-peak input & output voltage. Calculate
the voltage gain. Record these quantities in the data sheet.
2. Remove Cs, Vin should be kept the same as in step 1. Measure V out with
the Oscilloscope and record in the observations & calculate the stage
gain. How has the by pass capacitor Cs influenced the gain of stage?
3. Modify the circuit of Fig 1 by removing 1 uF capacitor in parallel with Rs.
Slowly -increase the input amplitude for maximum undistorted output.
Measure & record the input & output voltages. Calculate the voltage gain.
Compare this voltage gain to the two previous circuits.
4. Connect the common-gate amplifier circuit and adjust Vin for maximum
undistorted output. Measure and record Vin& Vout. Calculate the voltage
gain of stage. Compare the voltage gains of the three circuit
configurations.
Experiment No.15
Objective:
1. To study the JFET as a constant current source.
.
Materials Required:
1. Dc power supply
01
2. DMM
01
3. oscilloscope
01
4. Resistors
01
5. Bread board
01
Circuit Diagram
procedure:
1 Make the circuit as shown in the fig
2 Apply constant VDD =20V.
3
Short Gate to Source Junction so that VGs=0
4
Vary the value of Rd.
5
Measure the value of Id with DMM.
Observations
RD
ID
Experiment No.16
Objective:
To study the JFET as an analog switch
Apparatus:DC power supply
Oscilloscope
Function Generator
DMM
Resistor
01
01
01
01
01
Bread board
01
Circuit Diagram;
Procedure
Procedure
1
Make circuit on project board as shown in fig.
2
Apply 5 volt p-p Vdd through function generator
3 First put Vgs to 0 volt drain to source path become short and Vo across Rl is
very very small.
4
When Vgs =Vp the drain to source path become open and calculate Vo.
Observations:
Vgs
Vp-p
Vo
Calculated
Measured
Experiment No.17
Objective:
To study the JFET as a chopper.
Apparatus:DC power supply
Oscilloscope
Function Generator
DMM
Resistor
Bread board
Circuit Diagram:
01
01
01
01
01
01
Procedure:
1
Make the circuit as shown in the fig.
2
Make all the connections.
3
Apply 10 VP-P with function generator and take frequency at1KHZ.
4
Apply a dc square pulse of -4V at 6Hz.
5
Then measure the output and we get a chopped wave.
Observations:
Vgs
Vp-p
Vo
Calculated
Measured