How did the emitter follower amplifier get its name?

How did the emitter follower amplifier get its name?

This name is derived from the fact that the emitter voltage “follows” that of the base circuit – the circuit has unit voltage gain. The emitter follower transistor amplifier has a very straightforward circuit.

What is the current gain of an emitter follower?

In practice, the voltage gain of an emitter follower is between 0.8 and 0.999. The emitter follower circuit which was just discussed lacks to meet the requirements of the circuit current gain (A i) and the input impedance (Z i ).

Why is the common collector terminal called an emitter follower?

In the Common Collector transistor configuration, we use the collector terminal as common for both input and output signals. This configuration is also known as emitter follower configuration because the emitter voltage follows the base voltage.

How is biasing provided in an emitter follower?

The biasing is provided either by base resistor method or by potential divider method. The following figure shows the circuit diagram of an Emitter Follower. The input signal voltage applied between base and emitter, develops an output voltage V o across R E, which is in the emitter section. Therefore,

What makes an emitter follower a common collector?

The emitter follower or common collector circuit configuration provides a high input impedance and a low output impedance. This means that the emitter follower circuit provides an ideal buffer stage,…

What is the impedance of an emitter follower circuit?

Therefore, if a voltage line needs to be buffered it can be connected to the input of this circuit and the load that needs to be powered connects to the output of this circuit. In our circuit, specifically, the input impedance will be over 50KΩ and the output impedance will be about 5Ω.

What should bias point be for Class A emitter follower amplifier?

In many, if not most, applications, we can view the emitter follower as having unity voltage gain with the output voltage shifted down from the input voltage by one v BE drop. The bias point considerations for the Class A emitter-follower amplifier are the same as for the Class A CE amplifier.

How is the resistance of an emitter follower calculated?

As it is normally used as a buffer amplifier, this is the key parameter. The input resistance can easily be calculated for a circuit because it is β times the resistor R1, where β is the forward current gain of the transistor. The simplest way of connecting an emitter follower is to directly couple the input as shown below.

How did the common collector circuit get its name?

The common collector transistor circuit configuration gains its name from the fact that the collector circuit is common to both input and output circuits, the base being associated with only the input, then the emitter with the output only. The other name for the common collector is emitter follower.