What are the three major characteristics of the emitter follower?

The three major characteristics of the emitter follower are: 1. High input resistance, high efficiency in transmitting signal source signals; 2. Low output resistance, strong load capacity; 3. The voltage amplification factor is less than 1 and close to 1. The output voltage has the same phase as the input voltage and has following characteristics. Therefore, it is widely used as an output stage or intermediate isolation stage in practice.

#The operating environment of this article: windows10 system, thinkpad t480 computer.

What is an emitter follower

The emitter follower is a common collector amplifier circuit and is a widely used circuit. Its main function is to amplify the AC current to improve the load capacity of the entire amplifier circuit. In actual circuits, it is generally used as an output stage or isolation stage.

It is characterized by high input impedance and low output impedance, so the current required from the signal source is small and the load capacity is strong, so it is often used in the input stage and output stage of multi-stage amplifier circuits; it can also be used to connect two circuit to reduce the impact of direct connection between circuits and act as a buffer.

Features

The main features of the emitter follower circuit are: high input resistance, high efficiency in transmitting signal source signals; low output resistance, strong load capacity; voltage The amplification factor is less than 1 but close to 1, and the output voltage is in the same phase as the input voltage, and has following characteristics. Therefore, in practice, it is widely used as an output stage or intermediate isolation stage.

It should be noted that although the emitter follower circuit has no voltage amplification effect, it still has a current amplification effect, and therefore has a power amplification effect.

Circuit composition

The composition of the emitter follower circuit is shown in (a) in Figure 7.5.1, and (b) in Figure 7.5.1. its communication pathways. The functions of each component are basically the same as those of the common-emitter amplifier circuit, except that in addition to the role of RE in stabilizing the static operating point, RE can also be used as a load when the amplifier circuit is unloaded.

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