Difference Between CB and CC Amplifiers
Basic Difference
| Feature | Common Base (CB) | Common Collector (CC) |
|---|---|---|
| Common terminal | Base | Collector |
| Input | Emitter | Base |
| Output | Collector | Emitter |
CB: Signal flows emitter → collector
CC: Signal flows base → emitter
Key Characteristics
1. Input & Output Impedance
- CB amplifier: Low input impedance, High output impedance
- CC amplifier: High input impedance, Low output impedance
2. Voltage Gain
- CB: High voltage gain
- CC: Approximately 1 (unity)
3. Current Gain
- CB: Approximately 1 (low)
- CC: High (≈ ฮฒ + 1)
4. Phase Relationship
- CB: No phase reversal
- CC: No phase reversal
5. Power Gain
- CB: Moderate
- CC: Moderate (used for buffering)
Applications
Common Base (CB)
- High-frequency amplifiers (RF)
- Low input impedance applications
- Used in cascode amplifiers
Common Collector (CC) (Emitter Follower)
- Voltage buffer circuits
- Impedance matching
- Power supply/output stages
Simple Way to Remember
- CB: High voltage gain, low input impedance
- CC: Voltage follower (same voltage, more current)
Summary
CB Amplifier
- High voltage gain
- Low input impedance
- Used for high-frequency signals
CC Amplifier
- High current gain
- High input impedance
- Voltage gain ≈ 1
- Used as buffer