Experiment Name- Study of Single Stage Current Series Feedback Amplifier

American International University – Bangladesh (AIUB) Faculty of Engineering Analog Electronics – 2 (LAB)

Experiment No# 5 Experiment name: Study of Single Stage Current Series Feedback Amplifier Objectives: The objective of the experiment is to 1. Measure the quiescent operating point of the given feedback amplifier, 2. Plot the frequency response curve of the feedback amplifier circuit, 3. Determine the lower and upper cut off frequency of the amplifier circuit from the response curve. Equipments required: 1. 2. 3. 4. 5. 6. 7.

Oscilloscope Power supply Multimeter Transistor – C828 Capacitors 22 μ f, 100 μ f Resistors 22 KΩ, 6.8 KΩ, 1.5 KΩ, 680 Ω Signal generator

Circuit Diagram: VCC = 9 V

R1

RC

22 K

1.5 K

22 uf

C828 22 uf

RL R2 Ei

6.8 K

RE

S

680

100 uf

Fig: 1 Current Series feedback amplifier. Procedure: 1. Connect the circuit according to the figure 1.

2.2 K

2. Measure VCC, VCE and VC. The quiescent operating point collector current is given by V V I C  CC C . RC 3. Connect circuit without feedback (s is closed). Apply the ac signal Voltage at 100 mV at frequency of 1 KHz. Measure the output voltage. Now open the C and find the output voltage, and find the gain of the amplifier in the two cases. 4. Connect the circuit with the feedback (S is open). Now vary the input signal frequency with a constant input voltage. Measure output voltage at each frequency. Data Table: Ei = 100 mV Serial #

Frequency f (KHz)

V Gain  O  Ei

Output VO (volts)

  

Report: 1. Draw the frequency response curve. 2. From the response curve, find out lower and upper cut-off frequencies.

Emitter Follower Circuit diagram: VCC = 9 V

10 K C828 20 uf Ei

20 K

20 uf 1K

1K

Fig: 2: Emitter follower Procedure: 1. Connect the circuit according to the figure 2. 2. Measure VCC, VCE and VC. The quiescent operating point collector current is given by V V I C  CC C . RC 3. Connect circuit without feedback (s is closed). Apply the ac signal Voltage at 100 mV at frequency of 1 KHz. Measure the output voltage. Now open the C and find the output voltage, and find the gain of the amplifier in the two cases.

4. Connect the circuit with the feedback (S is open). Now vary the input signal frequency with a constant input voltage. Measure output voltage at each frequency. Data Table: Ei = 100 mV Serial #

Frequency f (KHz)

Output VO (volts)

V Gain  O  Ei

Report: 1. Draw the frequency response curve. 2. From the response curve, find out lower and upper cut-off frequencies.

  