04-01-2013, 04:37 PM
Voltage Shunt Feedback Amplifier
Voltage Shunt Feedback Amplifier.docx (Size: 333.64 KB / Downloads: 41)
THEORY:
When any increase in the output signal results into the input in such a way as to cause
the decrease in the output signal, the amplifier is said to have negative feedback.The
advantages of providing negative feedback are that the transfer gain of the amplifier with
feedback can be stablised against varations in the hybrid parameteresof the transistor or the
parameters of the other active devices used in the circuit. The most advantage of the
EC-I Lab Manual EC-261
BAPATLA ENGINEERING COLLEGE (Autonomous):: BAPATLA
negative feedback is that by propere use of this, there is significant improvement in the
frequency respponse and in the linearity of the operation of the amplifier.This disadvantage
of the negative feedback is that the voltage gain is decreased.
PROCEDURE:
1. Connections are made as per circuit diagram.
2. Keep the input voltage constant at 20mV peak-peak and 1kHz frequency.For different
values of load resistance, note down the output voltage and calculate the gain by using the
expression
Av = 20log(V0 / Vi ) dB
3. Remove the emitter bypass capacitor and repeat STEP 2.And observe the effect of
feedback on the gain of the amplifier.