What is a transistor, the principle, application, and historical development of transistors 3

2. Field Effect Transistor (FET)

Field effect transistor is a three terminal semiconductor device consisting of an n-type or p-type semiconductor channel and two control electrodes. The working principle of FET is to use an external voltage to control the channel resistance, thereby controlling the size of the drain current.

There are two types of FET, namely MOSFET and JFET. In MOSFET, the channel is separated by an extremely thin oxide layer, and the control electrode is the gate. The drain and source are connected to the channel, respectively. In JFET, the channel is composed of a p-type or n-type semiconductor material, and the control electrode is the gate. The drain and source are connected to the channel, respectively.transistor

3. Bipolar Field Effect Transistor (BGFET)

Bipolar field-effect transistor is a device that combines the characteristics of BJT and FET, consisting of a common base and two control electrodes. The working principle of BGFET is to use an external voltage to control the base current, and then control the size of the drain current.

4、 The Application of Transistors

transistor are widely used in various electronic devices, such as amplifiers, switches, oscillators, computers, mobile phones, televisions, etc. The following are specific applications of transistors in some fields:

1. Amplifier

A transistor amplifier is an electronic device that amplifies weak signals, which can amplify the input signal to a sufficiently large level, making it easier for subsequent circuits to process. Common amplifiers include single tube amplifiers, common emitter amplifiers, common base amplifiers, and common collector amplifiers.