Amplifier Configurations | Generated by AI
Here’s a comprehensive explanation of the three basic amplifier configurations—Common Emitter (CE), Common Collector (CC) (also known as Emitter Follower), and Common Base (CB)—focusing on their structure, signal characteristics, advantages, disadvantages, and typical applications.
🔷 1. Common Emitter (CE) Amplifier
🔧 Configuration
- Input: Applied between base and emitter.
- Output: Taken from collector and emitter.
- Common terminal: Emitter is common to both input and output.
🔍 Key Characteristics
| Property | Description | |————————-|————————————| | Voltage Gain | High | | Current Gain | Moderate to high | | Power Gain | High | | Phase Shift | 180° (inverted output) | | Input Impedance | Moderate | | Output Impedance | Moderate |
✅ Advantages
- Good for voltage and power amplification.
- Most widely used configuration.
❌ Disadvantages
- Inverts the signal (180° phase shift).
- Less suitable for impedance matching.
🧰 Applications
- General-purpose signal amplification.
- Audio amplifiers.
- Intermediate stages in amplifiers.
🔷 2. Common Collector (CC) Amplifier — Emitter Follower
🔧 Configuration
- Input: Applied between base and collector.
- Output: Taken from emitter and collector.
- Common terminal: Collector is common.
🔍 Key Characteristics
| Property | Description | |————————-|—————————————-| | Voltage Gain | Approximately 1 (unity gain) | | Current Gain | High | | Power Gain | Moderate | | Phase Shift | 0° (no inversion) | | Input Impedance | High | | Output Impedance | Low |
✅ Advantages
- Excellent buffer stage.
- Good for impedance matching (high input, low output impedance).
- No signal inversion.
❌ Disadvantages
- No voltage gain.
- Not suitable as a stand-alone amplifier where voltage amplification is needed.
🧰 Applications
- Buffer between stages.
- Driving low-impedance loads.
- Voltage followers.
🔷 3. Common Base (CB) Amplifier
🔧 Configuration
- Input: Applied between emitter and base.
- Output: Taken from collector and base.
- Common terminal: Base is common.
🔍 Key Characteristics
| Property | Description | |————————-|——————————————| | Voltage Gain | High | | Current Gain | Less than 1 | | Power Gain | Moderate | | Phase Shift | 0° (no inversion) | | Input Impedance | Very low | | Output Impedance | High | | Frequency Response | Very wide (good for high-frequency use) |
✅ Advantages
- Excellent high-frequency response.
- Stable operation.
❌ Disadvantages
- Low input impedance—requires careful design of the driving stage.
- Limited current gain.
🧰 Applications
- RF (radio frequency) amplifiers.
- High-frequency signal amplification.
- Impedance matching (for low-impedance sources to high-impedance loads).
🧠 Summary Table
| Configuration | Voltage Gain | Current Gain | Phase Shift | Input Z | Output Z | Application |
|---|---|---|---|---|---|---|
| Common Emitter (CE) | High | High | 180° | Medium | Medium | General amplification |
| Common Collector (CC) | ≈1 (unity) | High | 0° | High | Low | Buffering, impedance matching |
| Common Base (CB) | High | <1 | 0° | Low | High | High-frequency use |
Would you like visual diagrams of these configurations or an example circuit analysis for one of them?