The low frequency signal mode of a field-effect transistor (FET) refers to the behavior of the transistor when it is operating in its linear region, where the output voltage is proportional to the input voltage. This mode is also called the "small-signal" mode.

In this mode, the FET behaves like a voltage-controlled resistor, with the input voltage controlling the resistance between the drain and source terminals. The resistance of the FET is highest when the gate-source voltage (VGS) is zero, and decreases as VGS increases.

The low frequency signal mode is important for many applications of FETs, such as in amplifiers and filters, where small changes in input voltage need to be amplified or filtered. It is also important in the design of FET-based analog circuits, where the linear response of the FET is crucial for accurate signal processing.

Fig shows FET amplifier biased using the combination of self bias and voltage divider, the capacitor that effect the low frequency that effect the low frequency response on the input coupling capacitor C1 and C2 and source bypassed capacitor Cs. The equivalent circuit is shown in figure below.

This note is taken from MSC physics, Nepal.

This note is a part of the Physics Repository.

Previous topic: Energy stored by L and C in LCR parallel circuit excited at the resonant frequency W

Next topic: Upper and lower cut off frequency of an amplifier

Explore

posts on Naya and its networks

Collections