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8/13/2019 349 28 Lab-manual Lab-manual Op Amp 3e LabManual
Three basic op-amp circuits are investigated: a voltage follower, a noninverting amplifier,and an inverting amplifier. Each circuit is tested with dc input voltages, and then with ac
inputs. The output voltage levels are measured, and the amplitude and phase relationships
between input and output are noted.
Equipment
Plus-minus DC Power Supply—(0 to ±30 V, 50 mA)DC Power Supply—(0 to 12 V, 50 mA)
Two DC Voltmeters
OscilloscopeSinusoidal Signal Generator—(1 kHz, ±5 V)
Circuit Board
Op-amp—741 or similar alternative
0.25 W resistors—(2 × 56 k Ω), 8.2 k Ω, 270 Ω, 150 Ω, (2 × 68 Ω)
Procedure 1 Voltage Follower
1-1 Connect an op-amp as a voltage follower as shown in Fig. 1-1. Connect the power
supply, dc voltage source, voltmeters, and oscilloscope, as illustrated.
1-2 Set the power supply voltage to ±12 V, and adjust the voltmeters as necessary tomonitor the op-amp dc input and output voltage levels.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
Figure 1-1 Voltage follower circuit and connection diagram.
1-3 Adjust the input voltage to +1 V, +2 V, and +3 V in turn. In each case, record the
output voltage on the laboratory record sheet.
1-4 Repeat Procedure 1-3 using levels of –1 V, –2 V, and –3 V.
1-5 Disconnect the dc source, substitute the signal generator in its place, and apply a ±5
V, 1 kHz sinusoidal input signal. Adjust the oscilloscope to monitor the ac input
and output of the circuit.1-6 Measure the circuit ac output voltage and the input/output phase relationship.
1-7 Adjust the signal amplitude to ±2 V and ±3 V in turn, and measure the output ineach case. Record the results on the laboratory record sheet.
Procedure 2 Noninverting Amplifier
2-1 Connect an op-amp as a noninverting amplifier as shown in Fig. 1-2. Connect the
power supply, dc voltage source, voltmeters, and oscilloscope as illustrated.
2-2 Set the power supply voltage to ±12 V. Note that the resistors are R1 = 8.2 k Ω and R2 = 150 Ω, as in the first part of Example 1-3 in the text book.
2-3 Adjust the input voltage to +50 mV and 75 mV in turn. In each case, record the
output voltage on the laboratory record sheet, and calculate the voltage gain.2-4 Repeat Procedure 2-3 using input levels of –50 mV and –75 mV.
2-5 Disconnect the dc source, and substituting the signal generator in its place, apply a
±25 mV, 1 kHz sinusoidal input signal.
2-6 Record the circuit output voltage and the input/output phase relationship.
2-7 Adjust the input voltage to ±50 mV. Record the output amplitude and calculate the
voltage gain.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
2-8 Change R3 to approximately 111 Ω (use two series-connected 56 Ω resistors), as in
the second part of Example 1-3 in the text book.
2-9 Repeat Procedure 2-7.
Figure 1-2 Noninverting amplifier circuit and connection diagram.
Procedure 3 Inverting Amplifier
3-1 Connect an op-amp as an inverting amplifier as shown in Fig. 1-3. Connect the
power supply, dc voltage source, voltmeters, and oscilloscope as illustrated.3-2 Set the power supply voltage to ±12 V. Note that the resistors are R1 = 8.2 k Ω and
R2 = 270 k Ω, as in the first part of Example 1-4 in the text book.
3-3 to 3-7 Repeat Procedure 2-3 through 2-7.
3-8 Change R2 to approximately 137 Ω (use two series-connected 68 Ω resistors), as in
the second part of Example 1-4 in the text book.
3-9 Repeat Procedure 2-7.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
Figure 1-3 Inverting amplifier circuit and connection diagram.
Analysis
1 Discuss the voltage follower input and output voltage amplitudes and phase
relationships.
2 Discuss the noninverting amplifier input and output voltage amplitudes and phaserelationships. Compare the experimental results to the calculated values in Example
1-3 in the text book.
3 Discuss the inverting amplifier input and output voltage amplitudes and phaserelationships. Compare the experimental results to the calculated values in Example
1-4 in the text book.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
An op-amp is connected to function as an inverting amplifier with its input grounded.The output offset voltage is measured and the input offset voltage is calculated. With the
op-amp connected as a voltage follower, the process of output offset nulling is
investigated. The input bias current is determined by inserting a resistor in series with
each input terminal, in turn, and measuring the resultant output voltage change. Input andoutput voltage ranges are checked by increasing the amplitude of a sinusoidal input signal
until peak clipping occurs. The op-amp open-loop gain is determined by us of a modified
inverting amplifier circuit.
Equipment
Plus-minus DC Power Supply—(0 to ±30 V, 50 mA)
DC Power Supply—(0 to 12 V, 50 mA)
Two DC Voltmeters
OscilloscopeSinusoidal Signal Generator—(100 Hz, ±15 V)
Circuit Board
Op-amp—741 or similar alternative0.25 W resistors—10 Ω, 100 Ω, 1.5 k Ω, 5.6 k Ω, 10 k Ω, (2 × 100 k Ω), 1 MΩ
Potentiometer—10 k Ω
Procedure 1 Offset Voltage Measurement
1-1 Connect an op-amp as an inverting amplifier with the input grounded as shown in
Fig. 2-1. Connect the power supply and voltmeter as illustrated.
1-2 Set the power supply to ±12 V, record the measured output offset voltage on the
laboratory record sheet, and calculate the input offset voltage.1-3 Calculate the input offset voltage due to the specified maximum input bias current:
( I B(max) × 10 Ω). Compare this to the input offset voltage determined from the
measurements to check that it does not introduce a significant error.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
2-2 Set the power supply voltage to ±12 V, and adjust the nulling potentiometer to give
zero output voltage. If the output cannot be completely nulled, record the V o level.
2-3 Switch off the supply, remove the grounding connection from the op-amp
noninverting input terminal, and reconnect it to ground via a 1 MΩ resistor.
2-4 Switch the supply on again, and note the change in output voltage ∆V o (from the V o
nulled level). Calculate the input bias current at the op-amp noninverting terminal.2-5 Switch off the supply, remove the connection from the op-amp inverting input to
the output, and reconnect it to the output via a 1 MΩ resistor. Ground the
noninverting input directly once again.2-6 Switch the supply on again, and note the change in output voltage ∆V o (from the
nulled level). Calculate the input bias current at the op-amp inverting input.
2-7 Calculate the input offset current.
Procedure 3 Input and Output Voltage Ranges
3-1 Connect an op-amp voltage follower circuit as in Fig. 2-3 using 100 k Ω
resistors inseries with each input terminal, as illustrated. Set the power supply voltage to ±9 V.
3-2 Connect a sinusoidal signal generator to the voltage follower input, and anoscilloscope to monitor the input and output as shown. Note that the oscilloscope is
connected right at the op-amp noninverting input terminal.
3-3 Apply a 100 Hz sine wave input and increase its amplitude until the outputwaveform peaks just begin to flatten.
Figure 2-3 Circuit and connection diagram for input voltage range investigation.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
Figure 2-5 Circuit and connection diagram for determining the open-loop gain.
Analysis
1 Compare the measured input offset voltage to the specified input offset voltage forthe op-amp. Comment on the input offset voltage due to the maximum input bias
current.
2 Compare the measured input bias current and the measured input offset current tothe quantities specified for the op-amp. Calculate the maximum resistance value
that should be used at the input terminals of the op-amp.
3 Compare the measured input and output voltage ranges to the op-amp specifiedranges. Briefly explain the cause of the limits on the input and output voltage
swings.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
Several direct-coupled noninverting and inverting amplifier circuits designed in examplesin the text book are investigated. Tests are performed to determine the input/output
voltage relationships and to check input and output impedances.
Equipment
Plus-minus DC Power Supply—(0 to ±15 V, 50 mA)
OscilloscopeSinusoidal Signal Generator—(1 kHz, ±15 mV)
Circuit Board
Op-amp—741, LF353 (or alternatives with similar specifications)0.25 W resistors—100 Ω, (2 × 270 Ω), (3 × 1 k Ω), (2 × 15 k Ω), (2 × 18 k Ω), 47 k Ω,
(2 × 1 MΩ),
Capacitors—20 µF
Procedure 1 Direct-Coupled Noninverting Amplifier
1-1 Construct the 741 noninverting amplifier shown in Fig. 3-1 using the component
values determined in Example 3-3 in the text book. Connect the power supply,
signal generator, and oscilloscope as illustrated.
1-2 Set the power supply voltage to ±15 V, and adjust the signal generator to produce a±15 mV, 1 kHz sinusoidal input to the amplifier.
1-3 Measure the amplitudes of the input and output waveforms, record the measuredquantities on the laboratory record sheet, and calculate the amplifier closed-loop
voltage gain.
1-4 Connect a 1 MΩ resistor in series with the amplifier input. Check that the output
voltage is unaffected, to demonstrate that Zin >> 1 MΩ.1-5 Capacitor-couple a 100 Ω resistor in parallel with the op-amp output using a 20 µF
capacitor. Check that the output voltage is unaffected, to show that Zout << 100 Ω.
1-6 Construct the LF353 noninverting amplifier shown in Fig. 3-2 using the componentvalues determined in Example 3-4 in the text book. (Note that the pin connections
for the 353 are different from those for the 741.)1-7 Repeat Procedures 1-2 through 1-5.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
A summing circuit and a difference amplifier are investigated, both designed in text bookexamples. In each case various input voltages are applied and the output is monitored tocheck the input/output relationships.
Equipment Plus-minus DC Power Supply—(0 to ±15 V, 50 mA)Three DC Power Supplies—(0 to 12 V, 50 mA)
Three DC Voltmeters
Circuit BoardOp-amp—741, LF353 (or alternatives with similar specifications)
0.25 W resistors—560 Ω, (3 × 1.8 k Ω), 18 k Ω, (2 × 27 k Ω), (2 × 1 MΩ)
Procedure 1 Direct-Coupled Summing Circuits
1-1 Construct the inverting summing circuit shown in Fig. 4-1, using a 741 op-amp and
the component values determined in Example 3-9 in the text book.1-2 Connect the power supply, adjustable dc voltage sources, and voltmeters, as
illustrated, and set the power supply to ±15 V.
1-3 Set V 1 and V 2 to the voltage levels shown for Procedure 1-3 on the laboratory recordsheet, and record the output voltages in each case.
1-4 Change R3 to 18 k Ω and repeat the process using the levels listed for Procedure 1-4
on the laboratory record sheet
Figure 4-1 Two-input inverting summing circuit.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
1 Use Eq. 3-10 in the text book to calculate the output voltage levels for each set of
inputs for the summing circuit. Compare the calculated and measured quantities.
2 Use Eq. 3-12 in the text book to calculate the output voltage levels for each set of
inputs for the difference amplifier. Compare the calculated and measured quantities.3 Discuss the measured common mode gain for the difference amplifier.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
An instrumentation amplifier is constructed and tested. Common mode gain, differentialgain, common mode nulling, and output level shifting are all investigated. Each stage
gain is checked with various input voltages.
Equipment
Plus-minus DC Power Supply—(0 to ±15 V, 50 mA)
Two DC Power Supplies—(0 to 12 V, 50 mA)Two DC Power Voltmeters—(0 to ±15 V)
Oscilloscope
Sinusoidal Signal Generator—(1 kHz, ±15 mV)Circuit Board
Op-amps—(3 × 741)
Resistors—(2 × 27 k Ω), (3 × 12 k Ω)
Potentiometers—350 Ω, 10 k Ω
Procedure 1 Common Mode Voltage Gain and Level Shifting
1-1 Construct the instrumentation amplifier circuit shown in Fig. 5-1 using a ±15 V
supply and the component values determined in Example 3-12 in the text book.
(Note the use of decoupling capacitors C 1 and C 2 to ensure circuit stability.)1-2 Set R2 and R7 for maximum resistance, and set the dc offset voltage (V B) to zero.
1-3 Temporarily disconnect R4 and R6 from the outputs of A1 and A2, connect themtogether, and apply a 5 V input. Adjust R7 to produce 0 V dc output from A3.
1-4 Disconnect the 5 V input from R4 and R6 and reconnect the resistors to A1 and A2
once again. Do not alter R7 or V B.
1-5 Ground the A1 and A2 noninverting inputs, and record the level of V o from A3.1-6 Adjust V B to +1 V, +2 V, and +3 V in turn, and record the A3 output voltage in each
case.
1-7 Adjust V B to set V o3 to zero, reversing the polarity of V B if necessary. Record thelevel of V B.
1-8 Apply a +5 V common mode input to the A1 and A2 noninverting inputs, and recordthe output voltage from each op-amp.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
2 From the results of Procedure 1-8, Calculate the common mode gain for the circuit.
3 From the Procedure 2-2 and 2-3 results, calculate each stage gain and the overalldifferential gain. Compare these to the quantities in Example 3-12 in the text book.
4 Discuss the results of Procedures 2-4 through 2-6.
5 Compare the measured resistance of R2 with the calculated value in Example 3-12
in the text book.6 Determine the common mode rejection ratio for the circuit.
7 Explain the results of the ac measurements made in Procedure 3-2.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
Two capacitor-coupled voltage follower circuits designed in examples in the text bookare constructed and tested. Both circuits are tested for operation at 1 kHz, then the lower
cutoff frequency is determined. The input impedances of the circuits are also
investigated.
Equipment
Plus-minus DC Power Supply—(0 to ±15 V, 50 mA)
Oscilloscope
Sinusoidal Signal Generator—(10 Hz to 10 kHz)Circuit Board
Op-amp—741Resistors—3.9 k Ω, (2 × 68 k Ω), (2 × 120 k Ω), 1 MΩ
1-1 Construct the capacitor coupled voltage follower circuit shown in Fig. 6-1 using thecomponent values determined in Example 4-1 in the text book. Connect the power
supply, signal generator, and oscilloscope as illustrated.1-2 Set the power supply voltage to ±15 V, and adjust the signal generator to produce a
±1 V, 1 kHz sinusoidal input to the amplifier. Record the output voltage amplitude
on the laboratory record sheet and calculate the voltage gain.
1-3 Maintaining the input voltage constant, reduce the signal frequency until vo ≈ 0.707
vi. Record the lower cutoff frequency ( f 1).
1-4 Return the signal frequency to 1 kHz. Connect a 120 k Ω in series with the amplifier
input. Check the effect on the output voltage and calculate Zin.
1-5 Remove the 120 k Ω resistor and replace C 2 with a 0.39 µF capacitor. RepeatProcedure 1-3.
Procedure 2 High Zin Capacitor Coupled Voltage Follower
2-1 Construct the high input impedance capacitor coupled voltage follower circuitshown in Fig. 6-2 using the component values determined in Example 4-3 in the
text book. Connect the power supply, signal generator, and oscilloscope as
illustrated.
2-2 Repeat Procedures 1-2 and 1-3.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
Three capacitor-coupled amplifier circuits are constructed and tested: a noninvertingamplifier, a high input impedance noninverting amplifier, and an inverting amplifier. All
three circuits are tested for voltage gain, input impedance, and lower cutoff frequency.
The upper cutoff frequency of the inverting amplifier is also investigated.
Equipment
Plus-minus DC Power Supply—(0 to ±15 V, 50 mA)Oscilloscope
Sinusoidal Signal Generator—(10 Hz to 10 kHz)
Circuit BoardOp-amp—741, LF353 (or alternatives with similar specifications)
Resistors—27Ω, 220 Ω, 270 Ω, 1 k Ω, 2.2 k Ω, 4.7 k Ω, 12 k Ω, 18 k Ω, 47 k Ω, 120 k Ω,
1-2 Set the power supply voltage to ±15 V, and adjust the signal generator to produce a±50 mV, 1 kHz sinusoidal input (vi) to the amplifier. Record the output voltage
amplitude (vo) on the laboratory record sheet and calculate the amplifier gain.
1-3 Maintaining the input voltage constant, reduce the signal frequency until vo approximately equals 0.707 of the vo level at f = 1 kHz. Record the lower cutoff
frequency ( f 1).
1-4 Return the signal frequency to 1 kHz. Connect a 120 k Ω in series with the amplifier
input. Check the effect on the output voltage and calculate Zin.
Procedure 2 High Zin Capacitor Coupled Noninverting Amplifier
2-1 Construct the noninverting amplifier circuit shown in Fig. 7-2 using the component
values determined in Example 4-5 in the text book. Connect the power supply,signal generator, and oscilloscope as illustrated. (It may be necessary to connect a
20 pF capacitor in parallel with R2 for circuit stability.)
2-2 Repeat Procedures 1-2 and 1-3 using a 15 mV signal amplitude.
2-3 Return the signal frequency to 1 kHz. Connect a 1 MΩ in series with the amplifier
input. Check that the output voltage is unaffected, to demonstrate that Z in >> 1 MΩ.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
1 Discuss the performance of each of the noninverting amplifiers in relation to thespecified performance in the design examples. Consider the effect of component
tolerance on the lower cutoff frequency.
2 Calculate the new capacitor values for the circuit of Fig. 7-1 if C 1 is to set the lower
cutoff frequency.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
An inverting and a noninverting amplifier, both using single-polarity supply voltages, aretested for voltage gain and frequency response. The effect of input bias voltage change is
also investigated.
Equipment
Plus-minus DC Power Supply—(0 to 30 V, 50 mA)
OscilloscopeSinusoidal Signal Generator—(10 Hz to 10 kHz)
Circuit Board
Op-amp—741Resistors—250Ω, 1 k Ω, 5.6 k Ω, 47 k Ω, (3 × 100 k Ω), (3 × 220 k Ω)
1-1 Construct the inverting amplifier circuit shown in Fig. 8-1 using the componentvalues determined in Example 3-6 and 4-6 in the text book. Use a +30 V supply and
R3 = R4 = 100 k Ω.
1-2 Connect the signal generator, and oscilloscope as illustrated.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
1-4 Maintaining the input voltage constant, reduce the signal frequency until vo
approximately equals 0.707 of the vo level at f = 1 kHz. Record the lower cutofffrequency ( f 1).
1-5 Still maintaining the input voltage constant, increase the signal frequency until vo
approximately equals 0.707 of the vo level at f = 1 kHz. Record the upper cutoff
frequency ( f 2).1-6 Set the signal voltage to zero, then use the oscilloscope to measure the dc voltage
level at the junction of R3 and R4 and at the op-amp output.
1-7 Connect another 100 k Ω resistor in parallel with R4 to alter the bias voltage at theop-amp noninverting input terminal.
1-8 Repeat Procedure 1-6.
1-9 Repeat procedure 1-3.
Procedure 2 High Zin Capacitor Coupled Noninverting Amplifier
2-1 Construct the noninverting amplifier circuit shown in Fig. 8-2 using the component
values determined in Example 4-7 in the text book. Use a +24 V supply.2-2 Connect the signal generator, and oscilloscope as illustrated.
2-3 Apply a 1 kHz sinusoidal input and adjust its amplitude to give a 5 V peak output.Record the input voltage amplitude (vi) on the laboratory record sheet and calculate
the amplifier gain.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
Figure 9-2 Inverting amplifier using an LF353 op-amp.
Analysis
1 Comment on the measured mid-frequency voltage gains for all three amplifiers.2 Compare the LM108 circuit upper cutoff frequencies measured for Procedures 1-2
and 1-4 with those determined in Example 5-5 in the text book.
3 Referring to Fig. 5-9 in the text book, estimate the cutoff frequencies for the 741
op-amp circuit for ACL = –100 and for ACL = –47. Compare to the measured resultsfor Procedures 2-2 and 2-3.
4 Using the LF353 circuit cutoff frequency determined for Procedure 3-3, calculate
the op-amp GBW, and compare it to the specified GBW for an LF353.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
A 741 voltage follower is constructed and tested to determine slew rate, small signalcutoff frequency, and slew rate limited cutoff frequency. Two noninverting amplifier, one
using a 741 and one using a 353, are constructed and tested for the same quantities.
Equipment
Plus-minus DC Power Supply—(0 to ±15 V, 50 mA)
OscilloscopeFunction Generator (sine and square wave)—(100 Hz to 1 MHz)
Circuit Board
Op-amps—LM 108, 741, LF353 (or alternatives with similar specifications)Resistors—(2 × 1 k Ω), (2 × 10 k Ω), 47 k Ω, (2 × 100 k Ω), 1 MΩ
Procedure 1 Slew Rate Effects on a 741 Voltage Follower
1-1 Construct the inverting amplifier circuit shown in Fig. 10-1. Use a ±15 V supply,
and connect the signal generator, power supply, and oscilloscope as illustrated.
Figure 10-1 Voltage follower circuit using a 741 op-amp.
1-2 Adjust the signal generator to produce a 10 kHz, ±5 V square wave.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
1-3 Measure the rise time (t r ) of the circuit output waveform. Record t r on the laboratory
record sheet, and calculate the slew rate.
1-4 Replace the square wave with a 1 kHz sinusoidal wave, and adjust the sine wave
amplitude to give a 100 mV peak-to-peak output.
1-5 Maintaining the input voltage constant, increase the signal frequency until vo equals
70.7 mV p-to-p at the circuit upper cutoff frequency ( f 2). Record f 2.1-6 Reset the signal frequency to 1 kHz, and adjust the sine wave amplitude to give a
±5 V output.
1-7 Maintaining the input voltage constant, increase the signal frequency until vo falls to±(0.707 × 5 V) at the slew rate limited cutoff frequency ( f S). Record f S.
Figure 10-2 Noninverting amplifier using a 741 op-amp.
Procedure 2 Slew Rate Effects on a 741 Noninverting Amplifier
2-1 Construct the 741 noninverting amplifier circuit shown in Fig. 10-2. Use a ±15 Vsupply, and connect the signal generator, power supply, and oscilloscope as
illustrated.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
Procedure 3 Slew Rate Effects on an LF353 Noninverting Amplifier
3-1 Construct the LF353 noninverting amplifier circuit shown in Fig. 10-3. Use a ±15 V
supply, and connect the signal generator, power supply, and oscilloscope as
illustrated.
3-2 Apply a 100 kHz square wave input, and adjust its amplitude to produce a ±5 Vcircuit output.
3-3 Measure the rise time (t r ) of the circuit output waveform. Record t r on the laboratory
record sheet, and calculate the slew rate.3-4 Replace the square wave with a 1 kHz sinusoidal wave, and adjust the sine wave
amplitude to give a 100 mV p-to-p output.
3-5 Maintaining the input voltage constant, increase the signal frequency until vo equals70.7 mV p-to-p at the circuit upper cutoff frequency ( f 2). Record f 2.
2-6 Reset the signal frequency to 1 kHz, and adjust the sine wave amplitude to give a
±10 V output.
2-7 Maintaining the input voltage constant, increase the signal frequency until vo falls to
±7.07 V at the slew rate limited cutoff frequency ( f S). Record f S.
Analysis
1 Compare the slew rate determined in Procedure 1-3 with that specified for a 741 op-
amp.
2 Estimate the cutoff frequency for a 741 small signal voltage follower, and compareit to the f 2 measured in Procedure 1-5.
3 Calculate the slew rate limited cutoff frequency for the 741 voltage follower with a±5 V output, and compare it to the measured result for Procedure 1-7.
4 Compare the slew rate determined in Procedure 2-3 with that from Procedure 1-3.
5 Estimate the cutoff frequency for the 741 noninverting amplifier fromgain/frequency response Fig. 5-9 in the text book. Compare it to the cutoff
frequency determined in Procedure 2-5.
6 Calculate the slew rate limited cutoff frequency for the 741 noninverting amplifier
with a ±10 V output, and compare it to the measured result for Procedure 2-7.7 Discuss the f 2 and f S frequencies measured in Procedure 2-9.
8 Compare the slew rate determined in Procedure 3-3 with that specified for an
LF353 op-amp.9 Estimate the cutoff frequency for the LF353 noninverting amplifier from GBW
specified on the op-amp data sheet. Compare it to the cutoff frequency determined
in Procedure 3-5.
10 Calculate the slew rate limited cutoff frequency for the LF353 noninverting
amplifier with a ±10 V output, and compare it to the measured result for Procedure
2-7.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
2-1 Construct the noninverting Schmitt trigger circuit shown in Fig. 11-2 using the
component values from Fig. 8-15(b) in the text book. Use a ±15 V supply, and
connect the signal generator, power supply, and oscilloscope as illustrated.
2-2 Adjust the signal generator to produce a 1 kHz, ±7 V triangular wave input.2-3 Sketch the input and output waveforms on the laboratory record sheet, and record
the upper and lower trigger point voltages.
2-4 Adjust the amplitude of the input waveforms to ±8 V and ±6 V in turn. Measure andrecord the trigger point voltages in each case.
2-5 Change the input to a 1 kHz, ±7 V sinusoidal waveform. Once again sketch the
input and output waveforms, and record the trigger voltages.
Analysis
1 Compare the upper and lower trigger point voltages measured in Procedures 1-3through 1-5 to the triggering levels used in Example 8-3 in the text book.
2 Discuss the shape of the output waveforms obtained for Procedures 1-3 and 1-5.3 Discuss the output waveforms and triggering voltages obtained for Procedure 1-7.
4 Compare the upper and lower trigger point voltages measured in Procedures 2-3
through 2-5 with the triggering levels determined in Example 8-4 in the text book.5 Discuss the shape of the output waveforms obtained for Procedures 2-3 through 2-5.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
Differentiating and integrating circuits are constructed and tested for response to variousinput waveforms. The circuits use component values determined in Examples in the text
book, so that their performances may be compared to the expected performances.
2-1 Construct the integrating circuit shown in Fig. 12-2 using the component values
determined in Example 8-9 in the text book. Use a ±15 V supply, and connect the
signal generator, power supply, and oscilloscope as illustrated.
2-2 Adjust the signal generator to produce a 500 Hz, ±5 V square wave input.2-3 Sketch the input and output waveforms on the laboratory record sheet, and record
the positive and negative peak voltage levels.
2-4 Replace the square wave input with a 500 Hz, ±0.5 V sinusoidal wave.2-5 Observe the input and output waveforms and note the phase relationship.
2-6 Slowly reduce the sine wave frequency to discover the approximate frequency that
causes the output to shift by 3° from the correctly differentiated output wave
Analysis
1 Compare the waveforms obtained for Procedures 1-3 to the waveforms in Fig. 8-25(a) in the text book.
2 Compare the waveforms obtained for Procedures 1-5 to the waveforms in Fig. 8-25(b) and (c) in the text book.
3 Comment on the input-output sine wave phase relationship observed for Procedure
1-7, and on the maximum differentiating frequency determined for Procedure 1-8.4 Compare the waveforms obtained for Procedures 2-3 to the waveforms in Fig. 8-31
in the text book. Compare the peak output voltage levels to the design levels in
Example 8-8 in the text book.
5 Comment on the input-output sine wave phase relationship observed for Procedure
2-5, and on the minimum integrating frequency determined for Procedure 2-6.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
Saturating and nonsaturating precision half-wave rectifier circuits are constructed andtested. A precision clipping circuit with an adjustable clipping level is investigated, and a
precision clamping circuit is tested for response to square wave inputs.
Equipment
Plus-minus DC Power Supply—(0 to ±15 V, 50 mA)Oscilloscope
Sinusoidal Wave Generator—(1 kHz, ±15 mV)
Square Wave Generator—(10 kHz, ±5 V)Circuit Board
Op-amps—741, LF353 (or alternatives with similar specifications)Resistors—(2 × 470 Ω), 820 Ω, 1 k Ω, 1.5 k Ω, 2.2 k Ω, 3.9 k Ω, (2 × 22 k Ω)
Capacitors—200 pF, 5000 pF, 0.5 µF
Potentiometer—1 k Ω
Diodes—(2 × 1N914)Zener Diodes—(2 × 1N749)
Procedure 1 Precision Half-wave Rectifiers
1-1 Construct the saturating precision rectifier circuit shown in Fig. 13-1. Use a ±15 Vsupply, and connect the sinusoidal signal generator, power supply, and oscilloscope
as illustrated.
1-2 Adjust the signal generator to produce a 100 Hz, ±2 V sinusoidal wave input.Observe the half-wave rectified output waveform, and record its peak amplitude.
1-3 Switch the dc supply off, reverse the diode polarity, then switch the supply on
again.
1-4 Repeat procedure 1-2.1-5 Increase the signal frequency until the output becomes distorted. Record the
frequency at which the rectifier circuit is still operating satisfactorily.
1-6 Construct the nonsaturating precision rectifier circuit shown in Fig. 13-2 using thecomponent values determined in Example 9-1 in the text book. Use a ±15 V supply,
and connect the sinusoidal signal generator, power supply, and oscilloscope as
illustrated.
1-7 Repeat Procedure 1-2.
1-8 Switch the dc supply off, reverse the polarity of both diodes, then switch the supply
on again.
1-9 Repeat Procedure 1-2.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
2-1 Construct the clipping circuit shown in Fig. 13-3 using the component values
determined in Example 9-4 in the text book. Use a ±15 V supply, and connect the
signal generator, power supply, and oscilloscope as illustrated.
2-2 Adjust the signal generator to produce a 1 kHz, ±7 V sine wave input.2-3 Observing the output waveform on the oscilloscope, slowly adjust the moving
contact of R4 from one extreme to the other. Measure and record the clipped output
voltage peaks at each extreme.
Figure 13-3 Adjustable clipping circuit.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
3-1 Construct the clamping circuit shown in Fig. 13-4 using the component valuesdetermined in Example 9-7 in the text book. Use a ±12 V supply, and connect the
signal generator, power supply, and oscilloscope as illustrated.3-2 Adjust the signal generator to produce a 10 kHz, ±5 V square wave input. Measure
and record the peak-to-peak output voltage, and note the positive peak relationshipto ground level.
3-3 Switch the supply off, reverse the polarity of the diodes and of capacitor C 1.
3-4 Switch the supply on again, and repeat Procedure 3-2.
Analysis
1 Comment on the results of Procedures 1-2 through 1-8. How might the performance
of the saturating and nonsaturating circuits differ at high frequencies?2 Compare the results of Procedure 2-3 with the clipping range specified in Example
9-4. Show how the clipping circuit should be modified to clip off an adjustable
portion of the positive half-cycle while reproducing the complete negative half-
cycle.3 Comment on the input-output sine wave phase relationship observed for Procedure
1-7, and on the maximum differentiating frequency determined for Procedure 1-8.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
An astable multivibrator and a monostable multivibrator designed in examples in the text book are constructed and tested. The output frequency of the astable is measured for
comparison to the design frequency, and its capacitance value is altered to observe the
resultant frequency change. The pulse width of the monostable output is measured, andits capacitance value is altered to investigate its effect on the pulse width.
Equipment
Plus-minus DC Power Supply—(0 to ±15 V, 50 mA)
OscilloscopePulse Generator—(100 µs, 200 Hz, 2 V)
Circuit BoardOp-amp—LF353 (or alternative with similar specifications)
Resistors—3.3 k Ω, 39 k Ω, 56 k Ω, 1 MΩ
Capacitors—1100 pF, (2 × 0.1 µF)
Diode—1N914
Procedure 1 Astable Multivibrator
1-1 Construct the astable multivibrator circuit shown in Fig. 14-1, using the componentvalues determined in Example 10-1 in the text book. Use a ±10 V supply, andconnect the power supply, and oscilloscope as illustrated.
1-2 Sketch the capacitor waveform and the output waveform on the laboratory record
sheet, and record the waveform amplitudes and frequency.
1-3 Double the capacitance of C 1 by paralleling it with another 0.1 µF capacitor. Record
the effect on the waveform amplitudes and frequency.
Procedure 2 Monostable Multivibrator.
2-1 Modify the astable multivibrator to convert it into the monostable multivibrator
shown in Fig. 14-2, by including components D1 and C 2 and the necessaryconnecting links. Connect the signal generator, as illustrated.
2-2 Adjust the signal generator to produce a 200 Hz, +2 V, 100 µs pulse wave input.
2-3 Sketch the input, output, and C 1 waveforms on the laboratory record sheet, andrecord the waveform amplitudes and the output pulse width.
2-4 Double the capacitance of C 1 by paralleling it with another 0.1 µF capacitor. Record
the effect on the waveform amplitudes and the output pulse width.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
A triangular waveform generator designed in an example in the text book is constructedand tested. The output amplitude and frequency are monitored, and the effects of
component changes are measured. The circuit is modified for duty cycle adjustment, and
further modified to convert it into a voltage controlled oscillator. The output waveformsare investigated in each case.
Equipment
Plus-minus DC Power Supply—(0 to ±15 V, 50 mA)
DC Power Supply—(0 to 12 V, 50 mA)DC Voltmeter
OscilloscopeCircuit Board
Op-amps—(3 × 741) (or alternative with similar specifications)
Resistors—3.9 k Ω, 18 k Ω, (2 × 22 k Ω), (2 × 33 k Ω), 82 k Ω, (2 × 120 k Ω)
Capacitors—(2 × 0.015 µF)Diodes—(2 × 1N914)
Potentiometer—200 k Ω
Procedure 1 Triangular Wave generator Circuit
1-1 Construct the triangular waveform generator circuit shown in Fig. 15-1, using the
component values determined in Example 10-4 in the text book. Use a ±15 V
supply, and connect the power supply, and oscilloscope as illustrated.
1-2 Switch on the power supply, and monitor the output waveform from each section of
the circuit. Sketch the waveforms on the laboratory record sheet, and record the
waveform amplitudes and frequency.
1-3 Double the capacitance of C 1 by paralleling it with another 0.015 µF capacitor.Record the effect on the amplitude and frequency of the output waveforms.
1-4 Remove the additional capacitor from C 1, and halve the resistance of R2 by
paralleling it with another 18 k Ω resistor. Record the effect on the amplitude andfrequency of the output waveforms.
Procedure 2 Duty Cycle Adjustment
2-1 Switch off the supply, and modify the triangular wave generator for duty cycle
adjustment as shown in Fig. 15-2. Note that the component values used are from
Example 10-5 in the text book.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
Procedure 3 Voltage Controlled Triangular Wave Generator
3-1 Switch the supply off, and modify the circuit to convert it into a voltage controlled
oscillator, using the component values determined in Example 10-6 in the text
book, as illustrated in Fig. 15-3.
3-2 Switch the supply on again, and adjust V B to 9.5 V.3-3 Record the amplitudes and frequency of the output waveforms.
3-4 Adjust V B to 7.5 V and 3.5 V in turn, and repeat Procedure 3-3 in each case.
Figure 15-3 Voltage controlled triangular wave generator.
Analysis
1 Discuss waveforms obtained in Procedure 1-2, and compare the measured
frequency and amplitudes with the design quantities in Example 10-4 in the text book.
2 Discuss the effects of doubling the capacitance of C 1, and the effect of halving the
resistance of R2, as for Procedures 1-3 and 1-4.3 Compare the duty cycle range measurements made for Procedure 2-3 and 2-4 to the
design quantities in Example 10-5 in the text book.
4 Compare the results for Procedure 3-3 and 3-4 with the frequency range specified inExample 10-6 in the text book. Discuss the voltage controlled circuit operation.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
A timer astable multivibrator circuit designed in an example in the text book isconstructed and tested. The circuit is then modified into an adjustable frequency square
wave generator, which is then investigated for output waveform and frequency range. A
timer monostable circuit is next constructed and triggered from the square wave
generator. Finally, a sequential timer is constructed, and its output waveforms areinvestigated.
Equipment
DC Power Supply—(0 to 18 V, 50 mA)
OscilloscopeCircuit Board
Timers—(2 × 555)
Resistors—1 k Ω, 2.7 k Ω, 3.3 k Ω, (2 × 10 k Ω), 180 k Ω
1-1 Construct the 555 timer astable multivibrator circuit shown in Fig. 16-1, using thecomponent values determined in Example 10-9 in the text book. Use a +15 V
supply, and connect the power supply and oscilloscope as illustrated.
1-2 Switch on the power supply, and monitor the output waveform at terminal 3, and
the waveform across capacitor C 1. Sketch the waveforms on the laboratory record
sheet, record their amplitudes, pulse widths, and space widths, and show their time
relationships.1-3 Adjust the supply voltage to 5 V, and once again record the waveform amplitudes
pulse widths, and space widths.
Procedure 2 Timer Square Wave Generator
2-1 Switch off the supply, and reconstruct the circuit as shown in Fig. 16-2.
2-2 Set the supply to 12 V and set R2 to zero.
2-3 Switch the supply on and monitor the output waveform at terminal 3 and the
waveform across capacitor C 1. Sketch the waveforms on the laboratory record
sheet, record their amplitudes, pulse widths, and space widths, and show their timerelationships.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
3-1 Switch the supply off, and construct a monostable multivibrator capacitor-coupled
to the square wave generator, as illustrated in Fig. 16-3. Note that the monostablecomponent values are taken from Example 10-8 in the text book.
3-2 Set the supply to 12 V, and adjust R2 in the square wave generator to zero.
3-3 Switch the supply on, and monitor the monostable input and output waveforms.Sketch the waveforms on the laboratory record sheet, record their amplitudes, pulse
widths, and space widths, and show their time relationships.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
Figure 16-3 Timer monostable multivibrator triggered from an astable.
Figure 16-4 Sequential timer.
Procedure 4 Sequential timer
4-1 Switch the supply off, and construct the astable multivibrator controlled from thesquare wave generator, as shown in Fig. 16-4.
4-2 Switch the supply on, and monitor the square wave generator output and the astable
output. Sketch the waveforms on the laboratory record sheet, record theiramplitudes, pulse widths, and space widths, and show their time relationships.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
A phase shift oscillator designed in an example in the text book is constructed and testedfor output amplitude and frequency. The circuit is then modified to include voltage
divider amplitude stabilization, and its output is further investigated. A quadrature
oscillator is similarly investigated with and without amplitude stabilization. A Wein
bridge oscillator, also designed in a text book example, is constructed and tested. In thiscase, diode amplitude stabilization is used, and its the effect on the output is measured.
Equipment
DC Power Supply—(0 to 18 V, 50 mA)
OscilloscopeCircuit Board
Op-amps—(2 × 714) (or alternative with similar specifications)
Resistors—1.2 k Ω, (3 × 6.8 k Ω), (3 × 8.2 k Ω), 10 k Ω, (2 × 15 k Ω), (2 × 22 k Ω),
(2 × 33 k Ω), (2 × 56 k Ω), (2 × 68 k Ω), (2 × 220 k Ω)Capacitors—(3 × 3300 pF), (3 × 0.01 µF)
Diodes—(4 × 1N914)
Procedure 1 Phase Shift Oscillator
1-1 Construct the phase shift oscillator circuit shown in Fig. 17-1 leaving the diodes outof the circuit at this time. Use a ±12 V supply, and connect the power supply and
oscilloscope as illustrated.
1-2 Switch on the power supply, and monitor the waveforms at the op-amp output and
at the junction of R1 and C 1. Sketch the waveforms on the laboratory record sheet
and record their amplitude and frequency.
1-3 Switch the power supply off, and install the diodes to include the amplitudestabilization components in the circuit.
1-4 Switch the power supply on, and once again record the waveform amplitudes and
frequency.
Procedure 2 Quadrature Oscillator
2-1 Construct the quadrature oscillator circuit shown in Fig. 17-2 leaving the diodes out
of the circuit at this time. Use a ±10 V supply, and connect the power supply and
oscilloscope as illustrated.
2-2 Switch on the power supply, and monitor waveforms at the output of each op-ampand at the junction of R2 and C 2. Sketch the waveforms on the laboratory record
Operational Amplifiers & Linear Ics, 3/e David A. Bell
3-1 Construct the Wein bridge oscillator circuit shown in Fig. 17-3 leaving the diodes
out of the circuit at this time. Use a ±10 V supply, and connect the power supply
and oscilloscope as illustrated.
3-2 Switch on the power supply, and monitor the waveforms at the op-amp output andat its noninverting input. Sketch the waveforms on the laboratory record sheet and
record their amplitude and frequency.
3-3 Switch the power supply off, and install the diodes to include the amplitudestabilization components in the circuit.
3-4 Switch the power supply on, and once again record the waveform amplitudes and
frequency.
Figure 17-3 Wein bridge oscillator.
Analysis
1 Compare the waveforms obtained for Procedures 1-2 to the design quantities in
Example 11-1 in the text book.
2 Analyze the amplitude stabilized phase shift oscillator circuit to determine theexpected output amplitude. Compare the calculated and measured quantities.
3 Analyze the quadrature oscillator to determine the output frequency and the output
amplitude with and without amplitude stabilization. Compare the calculated
quantities to the measured quantities in Procedure 3.
4 Compare the waveforms obtained for Procedures 3-2 to the design quantities in
Example 11-3 in the text book.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
Two second-order filter circuits designed in examples in the text book are constructed
and tested. A low-pass filter is tested for upper cutoff frequency and output falloff rate. A
high-pass filter is tested for lower cutoff frequency, falloff rate, and circuit upper cutofffrequency.
Equipment
DC Power Supply — (±15 V, 50 mA)Oscilloscope
Sinusoidal Signal Generator — (100 Hz to 11 MHz, ±1 V)
Op-amps —(741, 108) (or alternative with similar specifications)Resistors —(4 × 4.7 k Ω), 18 k Ω, 33 k Ω, 39 k Ω
Capacitors —30 pF, (2 × 1000 pF), 2000 pF,
Circuit Board
Procedure 1 Low-pass Filter
1-1 Construct the second-order low-pass filter circuit shown in Fig. 18-1 using thecomponent values determined in Ex. 12-3 in the text book.
1-2 Before connecting the power supply, switch it on and adjust its output for V CC =
±12 V. Switch the power supply off, then connect it to the circuit and switch on.
1-3 Ground the circuit input and use the oscilloscope to check that the filter circuit isnot oscillating, then connect the oscilloscope and signal generator as illustrated.
1-4 Adjust the signal generator to apply a ±1 V, 100 Hz sinusoidal input to the filter.Check that the output displayed on the oscilloscope is also ±1 V, 100 Hz.
1-5 Keeping the input amplitude constant, increase the signal frequency until the output
level falls to approximately ±0.707 V. Record the filter upper cutoff frequency ( f c)
on the laboratory record sheet.1-6 Increase the signal frequency to 2 f c (keeping the input amplitude constant), then
measure and record the new peak level of the output voltage.
Procedure 2 High-pass Filter
2-1 Construct the second-order high-pass filter circuit shown in Fig. 18-2 using thecomponent values determined in Example 12-4 in the text book.
2-2 Before connecting the power supply, switch it on and adjust its output for V CC =
±15 V. Switch the power supply off, then connect it to the circuit and switch on .
2-3 Ground the circuit input and use the oscilloscope to check that the filter circuit is
not oscillating, then connect the oscilloscope and signal generator as illustrated.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
Fig. 18-2 Second-order high-pass filter circuit and connection diagram.
Analysis
1 Compare the low-pass filter cutoff frequency measured in Procedure 1-5 with the
design quantity in Example 12-3 in the text book.
2 Use the voltage levels measured in Procedures 1-5 and 1-6 to calculate the low-passfilter output falloff rate. Compare to the theoretical falloff rate.
3 Compare the high-pass filter cutoff frequency measured in Procedure 2-5 with the
design quantity in Example 12-4 in the text book.
4 Use the voltage levels measured in Procedures 2-5 and 2-6 to calculate the high- pass filter output falloff rate.
5 Calculate the upper cutoff frequency for the high-pass filter, and compare it to the
cutoff frequency measured in Procedure 2-7.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
Two band-pass filter circuits designed in examples in the text book are constructed andtested. A single-stage filter is tested to determine its upper and lower cutoff frequencies
and the output falloff rate beyond these frequencies. A state-variable filter using three op-
amps is tested for center frequency and upper and lower cutoff frequencies.
Equipment
DC Power Supply — (±15 V, 50 mA)
OscilloscopeSinusoidal Signal Generator — (10 Hz to 100 kHz, ±1 V)
Op-amps — (3 × 741) (or alternative with similar specifications)Resistors — (3 × 5.6 k Ω), (2 × 1 k Ω), (6 × 15 k Ω), 120 k Ω Capacitors —1000 pF, (2 × 0.01 µF), 0.1 µF
Circuit Board
Procedure 1 Single Stage Band-Pass Filter
1-1 Construct the single-stage band-pass filter circuit shown in Fig. 19-1 using thecomponent values determined in Example 12-7 in the text book.
1-2 Before connecting the power supply, switch it on and adjust its output for V CC =
±12 V. Switch the power supply off, then connect it to the circuit and switch on.1-3 Ground the circuit input and use the oscilloscope to check that the filter is not
oscillating, then connect the oscilloscope and signal generator to the circuit as
illustrated.1-4 Adjust the signal generator to apply a ±1 V, 3 kHz sinusoidal input to the filter.
Check that the output displayed on the oscilloscope is also ±1 V, 3 kHz.1-5 Keeping the input amplitude constant, decrease the signal frequency until the
output level falls to approximately ±0.707 V. Record the filter lower cutoff
frequency ( f 1) on the laboratory record sheet.
1-6 Reduce the signal frequency to f 1/2 (keeping the input amplitude constant), then
measure and record the new peak level of the output voltage.
1-7 Increase the signal frequency through 3 kHz (keeping the input amplitudeconstant) until the output level falls to approximately ±0.707 V once again.Record the filter upper cutoff frequency ( f 2) on the laboratory record sheet.
1-8 Still maintaining the input amplitude constant, further increase the signal
frequency to 2 f 2. Measure and record the new peak level of the output voltage.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
2-1 Construct the state-variable band-pass filter circuit shown in Fig. 19-2 using the
component values determined in Example 12-11 in the text book.
2-2 Before connecting the power supply, switch it on and adjust its output for V CC =
±15 V. Switch the power supply off, then connect it to the circuit and switch on.2-3 Ground the circuit input and use the oscilloscope to check that the filter is not
oscillating, then connect the oscilloscope and signal generator to the circuit as
illustrated. 2-4 Adjust the signal generator to apply a ±0.1 V, 1 kHz sinusoidal input to the filter.
Carefully adjust the frequency for maximum amplitude at the A2 output, which
occurs at the filter center frequency ( f o). Record f o and the output amplitude.
2-5 Keeping the input amplitude constant, reduce the signal frequency until the output
level falls to approximately ±0.707 V. Record the filter lower cutoff frequency ( f 1)
on the laboratory record sheet.
2-6 Increase the signal frequency through f o (keeping the amplitude constant) until the
output level falls to approximately ±0.707 V once again. Record the filter uppercutoff frequency ( f 2) on the laboratory record sheet.
Fig. 19-1 Single-stage band-pass filter circuit and connection diagram.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
Two series regulator circuits designed in examples in the text book are constructed andtested. An op-amp regulator is first tested for output voltage range, source effect, and
load effect. The circuit is modified to include current limiting, and the regulator short
circuit current is investigated. The second regulator circuit uses a 723 IC regulator. Tests
are performed to determine its line and load regulation.
Equipment
DC Power Supply—(0 to ±25 V, 250 mA)Voltmeter—(0 to 25 V)
Voltmeter—4½ Digital DVMAmmeter—(0 to 200 mA)Op-amp—741 (or alternative with similar specifications)
IC Voltage Regulator—723 (or alternative with similar specifications)
Resistors (0.25 W)—4.7 Ω, 270 Ω, 3.9 k Ω, 4.7 k Ω, 6.8 k Ω, 22 k Ω, 33 k Ω, 150 k Ω Resistors (0.5 W)—(2 × 10 Ω)
Resistors (2.5 W)—60 Ω
Variable Resistors (2 W)—150 Ω
Potentiometer—35 k Ω Capacitors —100 pF, 100 µF
BJTs—2N718, (2 × 2N3904) (or alternatives with similar specifications)
Zener diode—1N757 (or alternative with similar specifications)Circuit Board
Procedure 1 Op-amp Voltage Regulator
1-1 Construct the op-amp voltage regulator circuit shown in Fig. 20-1(a) and (b),
using a heat sink on transistor Q1. Note that the circuit uses the component values
determined in Examples 13-2, 13-4, and 13-5 in the text book.
1-2 Switch on the source voltage power supply, adjust it to 20 V, and adjust R4 to give
a 12 V output (V o). Note that a digital voltmeter that measures V o to at least three
decimal places should be used.1-3 Measure and record (on the laboratory record sheet) the voltage levels at thefollowing points with respect to ground: Q1 base, Q2 base, D1 cathode, R4 moving
contact.
1-4 Adjust the R4 moving contact to its maximum point in one direction, and then inthe other direction. Record the regulator output voltage in each case, then readjust
R4 for V o = 12 V.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
1-5 Adjust the source voltage to 22 V and then to 18 V. Record the output voltage
change in each case, then readjust the source voltage to 20 V.
1-6 Connect the 60 Ω, 2.5 W load resistor, ammeter, and switch (S 1) at the regulator
output, as illustrated in Fig. 20-1(c).
1-7 Carefully monitoring the output voltage, briefly close S 1 to switch the load
resistor into the circuit then open S 1 again. Record the measured output voltagechange that occurred when the load resistor was connected. Also record the load
current.
Fig. 20-1 Op-amp voltage regulator.
Procedure 2 Output Current Limiting
2-1 Switch off the source supply voltage and modify the circuit to include the current
limiting components (Q3, R6, and R7), as illustrated in Fig. 20-2. Connect the 150Ω adjustable load resistor ( RL) in place of the 60 Ω resistor in Fig. 20-1(c).
2-2 Set RL to its maximum resistance, and switch the source voltage on. Check that V o
= 12 V, and adjust R4 as necessary.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
2-3 Close S 1, and slowly adjust RL until V o commences to fall. Record V o and I L at this
point.
2-4 Further adjust RL toward zero resistance so that it short-circuits the regulator
output. Record the short circuit current ( I SC).
2-5 Open S 1 once again, and check that V o returns to its previous unloaded level.
Procedure 3 723 IC Voltage Regulator
3-1 Construct the 723 IC regulator circuit shown in Fig. 20-3. Note that the circuit
uses the component values determined in Examples 13-8 in the text book.
3-2 Set RL to its maximum resistance, then switch on the source voltage power supplyand adjust it to 17 V.
3-3 Measure and record V o and V R2. Note that a digital voltmeter that measures V o to
at least three decimal places should be used for measuring V o.
3-4 Adjust the source voltage to 18.7 V and then to 15.3 V. Record the output voltage
change in each case, then readjust the source voltage to 17 V.3-5 Close S 1, and slowly adjust RL until V o commences to fall. Record V o and I L at this
point.3-6 Further adjust RL toward zero resistance so that it short-circuits the regulator
output. Record the short circuit current ( I SC).
3-7 Open S 1 once again, and check that V o returns to its previous unloaded level.
Fig. 20-2 Current limiting test circuit.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
1 Compare the op-amp regulator voltage levels measured in Procedures 1-3 and 1-4
with the design quantities in Examples 13-2, 13-4, and 13-5 in the text book.2 Using the voltage levels measured in Procedures 1-5 and 1-7, calculate the regulator
source effect, load effect, line regulation, and load regulation.
3 Compare the short circuit current measured in Procedure 2 to the design quantity inExample 13-6.
4 Compare the 723 regulator voltage levels measured in Procedure 3-3 to the design
quantities in Example 13-6 in the text book.
Operational Amplifiers & Linear Ics, 3/e David A. Bell
A BJT output class AB power amplifier with an op-amp driver is constructed and testedfor dc and ac performance. The dc voltage levels throughout the circuit are first checked
without the load resistor connected. The load resistor is connected, an ac input signal is
applied, and the amplifier waveforms, frequency response, output power, and efficiency
are investigated.
Equipment
DC Power Supply—(±17 V, 200 mA)DC Voltmeter—(0 to 50 V)
Two DC Ammeters (0 to 200 mA)OscilloscopeAudio Range Signal Generator
BJTs—2N718, 2N722 (or alternatives with similar specifications)
Heat sinks for BJTsDiodes—(2 × 1N914)
Op-amp—LF356 (or alternative with similar specifications)
Resistors (0.25 W)— (2 × 8.2 Ω), 470 Ω, (4 × 1.5 k Ω), (2 × 10 k Ω), 82 k Ω,
1-1 Construct the amplifier circuit shown in Fig. 21-1, using a heat sinks on both
BJTs. Leave the signal generator and load resistor ( RL) unconnected at this time.1-2 Switch on the power supply and adjust it for V CC = ±17 V.
1-3 Use the oscilloscope to check that the circuit is not oscillating.
1-4 Measure and record the dc voltage levels through the circuit as listed on thelaboratory record sheet.
1-5 Connect the 100 Ω load resistor and check that the dc output voltage remains
zero.
Procedure 2 AC Measurements
2-1 Connect the signal generator to the amplifier input, and the oscilloscope tomonitor the input and output waveforms. Connect ammeters to measure the power
supply (dc) currents.
Operational Amplifiers & Linear Ics, 3/e David A. Bell