EMITTER FOLLOWER Meaning and
Definition
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An emitter follower is an electronic circuit configuration commonly used in amplifiers and signal processing applications. It is also known as a common collector configuration or a voltage follower.
In an emitter follower circuit, the output terminal is connected to the emitter of a transistor, while the input signal is applied to the base terminal. The collector terminal is connected to a fixed potential, usually a voltage source. This configuration provides a high input impedance and low output impedance.
The primary function of an emitter follower is to provide impedance matching between stages of an electronic circuit. It allows for the transfer of signals from a high impedance source to a low impedance load without significant loss or distortion. It is particularly useful in scenarios where the load impedance needs to be isolated or decoupled from the source.
Due to its high input impedance, the emitter follower draws minimal current from the input source, ensuring low signal loss. This makes it an ideal choice for buffering or voltage regulation applications. It also exhibits a unity voltage gain, meaning the output voltage follows the input voltage closely while being one diode voltage drop below it.
In summary, an emitter follower is an electronic circuit configuration that provides impedance matching, isolation, and voltage gain close to unity. It finds applications in various fields, including audio amplification, sensors, analog and digital signal processing, and control systems.
Etymology of EMITTER FOLLOWER
The word "emitter follower" refers to a type of electronic circuit configuration widely used in analog electronics. In this configuration, an emitter follower amplifier stage is connected to a transistor, where the output signal is taken from the emitter terminal. The term "emitter follower" is derived from the fact that the emitter terminal follows or tracks the voltage changes of the input signal.
The etymology of the word can be broken down as follows:
1. Emitter: In a transistor, the emitter is one of the three terminals (the other two being the base and collector). It is named so because it emits majority charge carriers (electrons or holes) into the transistor.
2. Follower: In this context, "follower" refers to the behavior of the emitter terminal in the circuit. It follows or replicates the changes in voltage or current of the input signal while providing a low output impedance.
