Analog Electronics – Page 37
Feedback Amplifiers – Concept and Types
Feedback is the process of taking a portion of the output signal and returning it to the input of the amplifier.
Feedback is widely used in electronic circuits to control gain, improve stability, and reduce distortion.
Basic Feedback System
A feedback amplifier consists of three main parts:
- Input Signal
- Amplifier (Gain Block)
- Feedback Network
Output → Feedback Network → Returned to Input
Types of Feedback
1. Positive Feedback
- Feedback signal is in phase with input
- Used in oscillators
- Increases gain
Positive feedback can cause instability.
2. Negative Feedback
- Feedback signal is opposite phase
- Used in amplifiers
- Improves stability
- Reduces distortion
Advantages of Negative Feedback
- Stabilizes amplifier gain
- Reduces noise
- Improves bandwidth
- Reduces distortion
Types of Feedback Amplifiers
- Voltage Series Feedback
- Voltage Shunt Feedback
- Current Series Feedback
- Current Shunt Feedback
Important GATE Points
- Negative feedback improves bandwidth
- Gain becomes more stable
- Distortion reduces significantly
- Used in most practical amplifiers
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