04-01-2013, 04:39 PM
VOLTAGE SERIES FEEDBACK AMPLIFIER
[attachment=46540]
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 stabilized against variations in the hybrid parameters of the transistor or
the parameters of the other active devices used in the circuit. The most advantage of the
negative feedback is that by proper use of this, there is significant improvement in the
frequency response and in the linearity of the operation of the amplifier. This disadvantage of
the negative feedback is that the voltage gain is decreased.
In Current-Series Feedback, the input impedance and the output impedance are
increased. Noise and distortions are reduced considerably.
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
[attachment=46540]
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 stabilized against variations in the hybrid parameters of the transistor or
the parameters of the other active devices used in the circuit. The most advantage of the
negative feedback is that by proper use of this, there is significant improvement in the
frequency response and in the linearity of the operation of the amplifier. This disadvantage of
the negative feedback is that the voltage gain is decreased.
In Current-Series Feedback, the input impedance and the output impedance are
increased. Noise and distortions are reduced considerably.
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