ECE 334 LABORATORY EXPERIMENTS

Summer 1998

 

 

 

NUMBER

 

NAME

EXP DATE

EXPERIMENT 1

 

PN JUNCTION DIODES

6/8

EXPERIMENT 2

 

DIODE APPLICATIONS

6/10

EXPERIMENT 3

 

NPN BJT AMPLIFIERS

6/15

EXPERIMENT 4

 

DESIGN PROJECT 1

6/17

EXPERIMENT 5

 

DESIGN PROJECT 2

6/22
 
 
PROBLEM SESSION I

6/24

EXPERIMENT 6 & 7

 

DESIGN PROJECT 3

6/29,7/1

EXPERIMENT 8

 

OP-AMP AMPLIFIER CIRCUITS

7/6 
 

PROBLEM 

SESSION II

7/8

EXPERIMENT 9

RTL AND DTL INVERTERS

7/13

 

PROBLEM 

SESSION III

 7/15

 

 

All experiment write-ups are due one week after the completion date.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ECE 334 DESIGN PROJECT 1

 Spring 1998
 

BJT  Amplifier(DC design)
 
 

PURPOSE:

To carry out the DC design and testing of a BJT common-emitter amplifier
 
 

REFERENCE:

T. A. DeMassa,  "Electrical and Electronic Devices, Circuits and Instruments", West Publishing Company
 
 

PROCEDURE:

Carry out the DC design and testing of a NPN  BJT(2N2222) common-emitter amplifier. Use a power supply voltage VCC = 5V and DC collector current  IC = 2mA and let Q be in the middle of the DC load line.

The design must include the following:

1) DC circuit analysis
2) SPICE analysis
3) Electrical measurement verification.
 
 

DUE DATE:

The design project write-up is due March 3, 1998.
 
 
 
 
 
 
 
 
 
 
 
 
 

ECE 334  DESIGN PROJECT 2

Spring, 1998

BJT  Amplifier(AC Design)
 
 
 

PURPOSE: 

To  design and test a  BJT common-emitter amplifier using an NPN 2N2222
 
 

REFERENCE: 

T. A. DeMassa,  "Electrical and Electronic Devices, Circuits and Instruments", West Publishing Company.
 
 

PROCEDURE:

Design and build an NPN  BJT common-emitter amplifier that operates in the audio frequency range (500 to 10,000 hertz). The overall voltage amplification is to be at least 50. Also,  use coupling and bypass capacitors in the design. Furthermore, the design should  include a small unbypassed resistor rE (50 to 100ohms) that is to be placed in series with  the bypass resistors RE.  This additional resistor (by proper choice) provides voltage amplification that is independent of hfe. Use a power supply voltage VCC = 5V and DC collector current  IC = 2mA and let Q be in the middle of the DC load line.

The design must include the following:

1) Small-signal analysis
2) SPICE analysis
3) Electrical measurement verification.
 

DUE DATE:

The design project write-up is due March 10, 1998.
 
 
 
 
 

ECE 334  DESIGN PROJECT 3

Spring, 1998
 

BJT Buffer Amplifier
 
 

PURPOSE:

To  design and test a  BJT common-collector amplifier or emitter follower amplifier.
 
 

REFERENCE:

T. A. DeMassa,  "Electrical and Electronic Devices, Circuits and Instruments", West Publishing Company.
 
 

PROCEDURE:

Design and build a NPN  BJT common-collector amplifier(emitter follower) that operates in the audio frequency range(500 to 10,000 hertz). The overall voltage amplification is to be as close to 1 as possible using coupling and bypass capacitors. This BJT amplifier is also called a "buffer" amplifier and is used as an interface to a load to supply a larger amplified current.

The design must include the following:

1) Small-signal analysis
2) SPICE analysis
3) Electrical measurement verification.
 
 

ECE 334 LAB #8

Op Amp Amplifiers

 

Name:

ASU ID:

Lab Partner:

 

This lab involves a study of the properties of operational amplifiers connected in the inverting and non-inverting configurations, as well as the application of op-amps as band pass filters.

 

With most of the oscilloscopes, it is difficult to get clear waveforms for this lab. If you do not get clear waveforms on the scopes, just draw the expected waveforms.

I. Inverting Amplifier

  1. Connect the circuit as shown in figure 1(a).

    2. The pin configuration of the 741 operational amplifier is shown in figure 1(b).

     

     

     

    Figure 1(b): Pin configuration

     

     

  2. Use RL=1.8K, RF=RS=10K and RP=5k.

Measure the values of these resistors using the RLC meter. Use the PM6303 RLC meter.

Measured values:

RL=

RF=

RS=

RP=

 

 

 

Use only measured values for all the gain calculations.

 

3. Important Circuit Assembly Instructions:

Do not switch on the Function generator (Vs) before switching on the power supply.

Connect the op-amp across the bridge of the breadboard, or you will short the terminals of the op-amp.

Use two DC power supplies (Hewlett Packard 6218 power supply).

Check the circuit carefully before applying power.

First turn on the negative supply (-15V), then the positive supply, followed by the function generator.

Always turn on the DC power supply before applying the AC signal. Always turn off the AC signal before turning off the DC power supply.

Set the frequency of Vs to 1 KHz and the amplitude to 2V peak to peak.

4. Observe the output waveform on the oscilloscope. If the output is distorted, reduce the input voltage so that the output waveform is a perfect sine wave.

5. Plot both the input and output waveforms below.

 

Verify that both the input and output waveforms are out of phase.

6. Now measure the input and output voltages using a multimeter kept in the AC mode.

Vs=

Vo=

Gain= Vo/Vs=

 

7. Calculate new values for R2 and/or R1 to achieve a theoretical gain of 10. This requires changing R3 (R3 is always the parallel combination of R1 and R2). Obtain the resistances from the storage bin and measure their values using the RLC meter.

 

Measured values:

R1 (new) =

R2 (new) =

R3 (new) =

 

8. Replace the resistors with their respective new values.

9. Apply the voltage Vs again and observe the input and output waveforms on the oscilloscope.

10. Plot the observed waveform and attach with the write-up.

Finally, measure the input and output voltages using a multimeter (set in the AC mode).

 

Vs =

Vo =

Gain = Vo/Vs =

 

 

II. Non Inverting Amplifier

  1. Connect the circuit as shown in figure 2.
  2. Before connecting RF, RS and RP measure their exact values.

    3. RF =

    RS =

    RP =

     

  3. Observe the input and output voltages.
  4. Plot the input and output voltages and attach with this write-up. Verify that the input and output waveforms are in phase.

  5. Now measure the input and output voltages using a multimeter (set in the AC mode).

 

Vs =

Vo =

Gain = Vo/Vs =

 

III. Band Pass Filter

 

  1. Recognize the low pass filter and high pass filter circuits in figure 3.
  2. For the high pass filter, determine the value of resistances R1 and R2 to obtain a corner frequency of 300 Hz and a high frequency gain of 2. Let C1= 0.1 uF.
  3. For the low pass filter, compute the value of C2 so that the corner frequency is located at 8 kHz.
  4. Now, assemble the circuit as shown in figure 3, with component values obtained from steps 2 and 3.

    5. Check the circuit before applying power. The –15 V power supply should be turned on first.

  5. Record the values of the output voltage for different values of the input signal frequency, in the table below.

    6. 100Hz

    		  

    1kHz

    		  

    10kHz

    		  

    20kHz.

    		  

     

     

  6. Explain the values of the output voltage for different values of the input signal frequency.

 

 

 

P- SPICE SCHEMATIC

(Version Microsim 8.0)

 

  1. Construct the schematic for the circuit in figure 3. Use op-amp model uA741.

    2. Note: Verify the circuit at the inverting and non inverting terminals of each op-amp. Do not leave terminals floating, ground all the floating terminals.

  2. Save the schematic.
  3. Click on Analysis from the scroll-down menu and then select Setup. Chose the AC sweep option in the pop up window. Remember, to activate this option. Set the value of AC sweep to linear scales, and select the appropriate start and end frequencies for the scale.
  4. Simulate the circuit and run the probe.

    5. Note: The probe may be set up to run automatically after simulation. The probe can be run manually by selecting the Run Probe option from the Analysis scroll down menu.

  5. To observe the band pass filter characteristic curve, click on trace, and then select Add Trace.
  6. Divide the output voltage of op-amp 2 (V(U2:out)) by the input voltage of op-amp 1 (V(u1:+)).

    7. Note: If the desired waveform is not obtained, vary the frequency range in the AC sweep setup option and alter the scale of the trace to obtain a more accurate representation.

  7. Label the axes.
  8. Attach a copy of the schematic and the probe output with this write-up.

 

 

 

Discussion:

  1. What will happen if the RL in the inverting amplifier circuit is reduced to one-tenth it’s value? Explain.

    2.  

     

     

     

     

     

     

     

     

  2. Explain the results for the output voltage of the band pass circuit as the frequency is varied.