• Depending on the relative
polarity of fed back signal in to the circuit, there
are two types of feedback
> Negative feedback
> Positive feedback
Negative feedback results in
Reduced gain
Positive feedback are used in
oscillators.
Feedback amplifier
Negative
feedback circuits
• Reduces the gain
• Increases input impedance
• Better stabilized frequency
response
• Lower output impedance
• Reduced noise
• More linear operation
Feedback
connection types
• Voltage series feedback
• Voltage shunt feedback
• Current series feedback
• Current shunt feedback
Ø Here voltage
refers to small part of voltage as input to the feedback network
Ø Current refers
to tapping some part of output current through feedback
network.
Ø Series refers to
connecting feedback signal in series with the input signal
voltage.
Ø Shunt refers to
connecting feedback signal in shunt with the input signal
voltage
Ø Series feedback
connections increases the input resistance
Ø Shunt feedback
connections decreases the input resistance.
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