How do you find the impedance of an emitter follower?

How do you find the impedance of an emitter follower?

Output Impedance: if removing Re and Rc, Zout = 2Mohm/(100+1). With Rb and Rc in place, according to AoE formula, Z_source = 2Mohm/(100+1) + 10kohm + 1kohm = 30,801.980198 ohm (the resistance looking into emitter in the perspective of the load, or R_e).

What is the output impedance of emitter follower?

The input impedance of the emitter follower is found as the parallel equivalent resistance of the base resistors and the transistor input impedance. The output impedance is the impedance that the circuit presents to its load.

What is input impedance and output impedance?

The output impedance refers to the impedance, or opposition to current flow, of the component that often bears an electrical source to “drive” a load component. Meanwhile, the input impedance refers to the load component’s opposition to current flowing in from the electrical source.

What are the features of emitter follower?

Emitter follower circuit has a prominent place in feedback amplifiers. Emitter follower is a case of negative current feedback circuit….Characteristics

  • No voltage gain.
  • Relatively high current gain and power gain.
  • High input impedance and low output impedance.
  • Input and output ac voltages are in phase.

What is the value of gain in emitter follower?

approximately unity
The emitter follower (Figure 5.11(a)) is a buffer stage with high input impedance, low output impedance, and a gain of approximately unity.

What is high impedance output?

Hi-Z (or High-Z or high impedance) refers to an output signal state in which the signal is not being driven. The signal is left open, so that another output pin (e.g. elsewhere on a bus) can drive the signal or the signal level can be determined by a passive device (typically, a pull-up resistor). Synonyms.

How do you calculate input and output impedance?

The Output Impedance of an amplifier can be thought of as being the impedance (or resistance) that the load sees “looking back” into the amplifier when the input is zero. Working on the same principle as we did for the input impedance, the generalised formula for the output impedance can be given as: ZOUT = VCE/IC.

What is the main application of an emitter follower?

The emitter follower configuration is mostly used as a voltage buffer. These configurations are widely used in impedance matching applications because of their high input impedance.

How does an emitter follower work?

Emitter Follower. This is an emitter follower or buffer amplifier circuit, where the output is simply equal to the input minus a diode drop (about 700mV). It provides low output impedance to any circuit using the output of the follower, meaning that the output will not drop under load.

Why emitter follower is used in circuits?

The emitter follower is widely used as a buffer amplifier to reduce the loading on the previous stage and provide a lower impedance output for any following circuits. The electronic circuit design for the stage is also very straightforward and easy to accomplish.

What are the applications of an emitter follower?

Applications of Emitter Follower . The emitter follower has the following principal applications : (i) To provide current amplification with no voltage gain. (ii) Impedance matching. (i) Current amplification without voltage gain. We know that an emitter follower is a current amplifier that has no voltage gain (Aν = 1). There are many instances (especially in digital electronics) where an increase in current is required but no increase in voltage is needed.

What is the use of emitter follower?

In electronics, a common collector amplifier (also known as an emitter follower) is one of three basic single-stage bipolar junction transistor (BJT) amplifier topologies, typically used as a voltage buffer.

What are emitter follower configurations?

An emitter follower is one of the standard transistor configurations which is also referred to as common collector transistor configuration. Let’s try to first understand what’s an emitter follower transisto r and why it’s called a common collector transistor circuit.