solderic.com Common emitter amplifiers provide high voltage gain and moderate current gain, making them ideal for signal amplification applications, whereas common collector amplifiers offer high current gain with near-unity voltage gain, often used for impedance matching and buffering. Explore the rest of the article to understand how your choice between these amplifier types affects circuit performance.
Comparison Table
| Feature | Common Emitter (CE) Amplifier | Common Collector (CC) Amplifier |
|---|---|---|
| Configuration | Base input, emitter output, collector common | Base input, collector output, emitter common |
| Voltage Gain | High (typically 20 to 200) | Approximately 1 (unity gain) |
| Current Gain | Moderate to High (b times) | High (close to b plus 1) |
| Power Gain | High | Moderate |
| Input Impedance | Moderate (1kO to 10kO) | High (10kO to 100kO or more) |
| Output Impedance | High (several kO) | Low (few O to tens of O) |
| Phase Shift | 180deg phase inversion | No phase inversion (0deg) |
| Main Use | Voltage amplification | Impedance matching / Buffer |
| Load Driving Capability | Limited moderate load | Excellent for low impedance loads |
Introduction to Transistor Amplifier Configurations
Common emitter amplifiers offer high voltage gain and moderate input impedance, making them ideal for voltage amplification in audio and radio frequency circuits. Common collector amplifiers, also known as emitter followers, provide high input impedance and low output impedance, perfect for impedance matching and signal buffering. Your choice between these configurations depends on whether voltage gain or impedance matching is the primary requirement in your transistor amplifier design.
Overview of Common Emitter Amplifier
The common emitter amplifier is a widely used transistor configuration known for its high voltage gain and moderate input impedance, making it ideal for signal amplification. It features the emitter terminal as a common reference point for both input and output, enabling significant phase inversion between input and output signals. This amplifier type excels in providing wide frequency response and substantial power gain, making it a fundamental building block in analog electronics.
Overview of Common Collector Amplifier
The common collector amplifier, also known as an emitter follower, provides high input impedance and low output impedance, making it ideal for impedance matching applications. It offers a voltage gain close to unity but delivers significant current gain, allowing efficient driving of low-impedance loads. Your circuit benefits from excellent buffering capabilities and stable performance in signal amplification scenarios.
Circuit Diagrams and Basic Operation
The common emitter amplifier features a transistor with the emitter terminal grounded, input signals applied to the base, and output taken from the collector, providing significant voltage gain and phase inversion. In contrast, the common collector amplifier, also known as an emitter follower, connects the collector to the power supply, with input at the base and output at the emitter, delivering high current gain and unity voltage gain without phase shift. Understanding these circuit diagrams and basic operations helps you select the appropriate amplifier type for voltage amplification or impedance matching in electronic designs.
Voltage Gain Comparison
The common emitter amplifier typically offers a high voltage gain, often ranging from 20 to 200, making it suitable for signal amplification where voltage increase is essential. In contrast, the common collector amplifier provides a voltage gain close to unity (approximately 0.9 to 1), emphasizing current gain and impedance matching rather than voltage amplification. This difference is crucial in applications requiring either significant voltage boost or impedance buffering between circuit stages.
Input and Output Impedance Differences
Common emitter amplifiers exhibit moderate input impedance, typically ranging from a few kilo-ohms to tens of kilo-ohms, while their output impedance is relatively high, often several kilo-ohms. Common collector amplifiers, also known as emitter followers, have high input impedance, usually in the order of hundreds of kilo-ohms to mega-ohms, and very low output impedance, often less than 100 ohms. Understanding these impedance differences helps optimize Your circuit design for impedance matching and signal integrity.
Phase Relationship and Signal Inversion
The common emitter amplifier produces an output signal that is 180 degrees out of phase with the input, resulting in signal inversion, which is essential for applications requiring phase-shifted amplification. In contrast, the common collector amplifier, also known as an emitter follower, maintains the same phase between input and output signals, providing no signal inversion. Your choice between these amplifiers depends on whether phase inversion is critical for your circuit design needs.
Typical Applications of Common Emitter and Common Collector
Common emitter amplifiers are widely used in voltage amplification applications such as audio amplifiers and signal processing circuits due to their high voltage gain and moderate input/output impedance. Common collector amplifiers, also known as emitter followers, are typically employed in impedance matching and buffering stages because they provide high input impedance, low output impedance, and unity voltage gain. Your choice between these configurations depends on the need for voltage gain versus impedance matching in your electronic design.
Advantages and Limitations of Each Configuration
The common emitter amplifier offers high voltage gain and moderate input impedance, making it ideal for voltage amplification but suffers from phase inversion and limited bandwidth. The common collector amplifier, also known as an emitter follower, provides high input impedance, low output impedance, and unity voltage gain, making it suitable for impedance matching and buffering but lacks voltage amplification. Each configuration balances gain, impedance, and phase characteristics to suit specific signal processing requirements in electronic circuits.
Choosing the Right Amplifier for Your Design
Common emitter amplifiers provide high voltage gain and moderate input impedance, making them ideal for applications requiring amplification of weak signals with significant voltage swing. Common collector amplifiers, also known as emitter followers, offer high input impedance, low output impedance, and unity voltage gain, which makes them suitable for impedance matching and buffering in your circuit design. Selecting the right amplifier depends on whether your focus is voltage gain or impedance matching to optimize performance in your electronic system.
common emitter vs common collector amplifier Infographic
