Why a transistor has low input impedance and high output impedance?

Due to it, a small change in emitter current. This means that a small signal voltage variation at the input of the transistor produces a large emitter current variation. This shown that the input resistance of a transistor is low. This shows that the output resistance of the transistor is high.

What happens when input impedance is high?

In electronics, high impedance means that a point in a circuit (a node) allows a relatively small amount of current through, per unit of applied voltage at that point. In audio systems, a high-impedance input may be required for use with devices such as crystal microphones or other devices with high internal impedance.

What is high impedance and low impedance?

A high impedance microphone or guitar will usually output a greater signal (voltage) than a low impedance microphone. A low impedance microphone will lower the impedance of the entire line connected to it.

Which type of transistor has high input impedance?

The emitter follower or common collector is also widely used. Providing a high input impedance and low output impedance it acts as a buffer and provides only current gain – its voltage gain is unity. The common base is used in more specialist applications and is seen considerably less.

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.

Why is high output impedance bad?

in this case, if your amplifier has a high input impedance then the voltage will not drop on its input and thus your input voltage is maintained at the desired level. Low output impedance is desired to suck the maximum current from the circuit. High impedance means the circuit draws or gives little power to the signal.

What has the highest input impedance?

1. Which among the following circuit has the highest input resistance? Explanation: Voltage follower has the highest positive input resistance of any op-amp circuit. For this reason it is used to reduce voltage error caused by source loading.

What is meant by input 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 does high output impedance mean?

High impedance means the circuit draws or gives little power to the signal. low impedance means the circuit draws or gives more power to the signal.