What is a transistor, its principle, application and historical development

The transistor is an extremely important component. It is one of the most basic components in electronic devices and is also one of the cores of modern electronic technology. The appearance of the transistor has enabled electronic devices to become in size, lower in power consumption, faster in speed, and thus promoted the development of modern electronic technology. This article will introduce the history, working principle, types, and of transistors in detail.

1. Historical development of the transistor

The inventor of the transistor is American physicist William Shockley, John Bardeen, and Walterattain. They invented the transistor at Bell Labs in 1947. The transistor is made of semiconductor materials. Compared with vacuum tubes, it is smaller in size, in power consumption, faster in speed, and longer in life, thus it has been widely used.

2. Working principle of the transistor

The transistor is a threelayer semiconductor device, consisting of an n-type semiconductor and a p-type semiconductor, with a very thin layer of p-type semiconductor in between. These three layers are called emitter, base, and collector, respectively. The working principle of the transistor is to use an external voltage to control the base current, thereby controlling the size of the collector current

When a forward voltage is applied between the base and the emitter, electrons from the emitter move towards the base direction. At the same time, an electric field is between the base and the collector, which accelerates the electrons in the collector and thus forms the collector current. When a reverse voltage is applied between the base and the emitter, electrons in the emitter cannot move towards the base direction, and thus the base current cannot be formed, and thus the size of the collector current cannot be controlled.

3 Types of transistors

Transistors are divided into several types according to different working principles and structures, among which the commonly used ones are bipolar junction transistors (BJTs, field effect transistors (FETs), and bipolar gate field effect transistors (BGFETs), etc.

1. Bipolar junction transistor (BT)

The bipolar junction transistor is a three-layer semiconductor device, consisting of an n-type semiconductor and a p-type semiconductor, with a very thin layer of-type semiconductor in between. These three layers are called the emitter, base, and collector, respectively. The working principle of the BJT is to use an external voltage control the base current, thereby controlling the size of the collector current.

There are two types of BJTs, npn and pnp. In an npn BT, the emitter is an n-type semiconductor, the base is a p-type semiconductor, and the collector is an n-type semiconductor. In a pnp BT, the emitter is a p-type semiconductor, the base is an n-type semiconductor, and the collector is a p-type semiconductor.

2. Field transistor (FET)

The field effect transistor is a three-terminal semiconductor device, consisting of a channel of n-type or p-type semiconductor and two control electrodes. working principle of the 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, MOSFET and JFET. In a MOSFET, the channel is separated by a very thin oxide layer, and the control electrode is the gate. The drain and source are to the channel, respectively. In a JFET, the channel is made of a p-type or n-type semiconductor material, and the control electrode is the gate, and drain.

3. Bipolar Junction Field-Effect Transistor (BJFET)

The Bipolar Junction Field- Transistor (BJFET) is a device that combines the characteristics of both BJTs and FETs, consisting of a common base and two control electrodes. The principle operation of a BJFET involves using an external voltage to control the base current, which in turn controls the magnitude of the drain current.

4. Applications of Transistors

Transistors are widely used in various electronic devices such as amplifiers, switches, oscillators, computers, mobile phones, televisions, etc. Here are some specific applications of trans in different devices:

1. Amplifier

A transistor amplifier is an electronic device that amplifies a weak signal, which can be amplified to a sufficient level subsequent circuits to process more easily. Common amplifiers include single-transistor amplifiers, common-emitter amplifiers, common-base amplifiers, and common-collectorifiers.

2. Switch

A transistor can be used as a switch to control the flow of current. In digital circuits, transistors are often used as switches to logic operations and control the transmission of signals.

3. Oscillator

A transistor oscillator is an electronic device that can produce a continuous oscillating signal, which can a direct current power supply into a high-frequency alternating current signal. Transistor oscillators are widely used in television, broadcasting, radio communication, and other fields.

4.

Transistors are widely used in computers, such as CPUs and memories, and their speed, power consumption, heat, and reliability are all limited by transistors.

5. Mobile Phone

The application of transistors in mobile phones is very extensive, such as amplifiers, switches, oscillators, filters, etc., which can realize various such as communication, audio, and video in mobile phones.

6. Television

The application of transistors in televisions is also very extensive, such as amplifiers oscillators, drivers, etc., which can realize various functions such as images and sound in televisions.

In conclusion, as an extremely important electronic component, the transistor has one of the cores of modern electronic technology and is widely used in various electronic devices. With the continuous development of electronic technology, the application field of transistors will also continue to expand deepen.