Differences between ordinary transistors and other transistors

Transistors have the advantages of small power, small size, high reliability, fast response time, long life, and wide operating temperature range. Therefore, transistors are widely used in electronic circuits, such as television, tape recorders, computers, mobile phones, LED lighting, and other electronic devices. This article summarizes some information and hopes to provide valuable reference for readers.

Differences between general transistors and other transistors

General transistors refer to bipolar transistors (BJTs), which have the following differences compared to other transistors (such as field effect transistors, insulated gate bipolar transistors, etc.):

Composition principle: Bipolar transistors have a PNP or NPN structure and are composed of three regions (emission region, base region, and collector region). The thickness of the base region is very thin, and the output current can be manipulated by manipulating the input electrical signal. Field effect transistor (FET) is an N-type or P-type semiconductor device consisting of a drain, source, and gate. It is possible to manipulate the current between the drain and source by manipulating the gate voltage.

Control method: The control method for bipolar transistors is to control the output current by inputting the base current, while FETs adjust the output current by controlling the gate voltage.

Output characteristics: There is a proportional relationship between the output current and the input current of a bipolar transistor. The output current is usually greater than the input current, so it is often used in amplification circuits. There is an exponential relationship between the output current and the gate voltage of FETs, and there is no fixed proportional relationship between the output current and the input current. Therefore, FETs are commonly used in switching circuits.

Common categories: Bipolar transistors are widely used in low-frequency and high-frequency amplification circuits, while FETs are widely used in high-frequency and low-noise circuits.

Common types of transistors:

NPN transistor: This transistor consists of an N-base region and two P-regions (emitter and collector regions), and is the most common type of transistor. In NPN transistors, when a voltage is input to the base, current gradually flows from the emitter to the collector, thereby achieving current amplification or switching.

PNP transistor: This transistor consists of a P-type base region and two N-type regions (emitter and collector regions), as opposed to NPN transistors. In PNP transistors, when a negative voltage is input to the base, current gradually flows from the collector to the emitter, thereby achieving current amplification or switching.

MOSFET (Metal Oxide Semiconductor Field Effect Transistor): This type of transistor uses a metal oxide semiconductor structure, with strong input resistance and low power consumption, and can be used to manipulate current. MOSFET transistors have two electrodes (drain and source) and one gate. The current between the drain and source can be controlled by controlling the gate voltage.

JFET (Junction Field Effect Transistor): This type of transistor is also a field effect transistor composed of N-type or P-type semiconductor materials. It regulates the current between the drain and source electrodes by controlling the gate voltage.

IGBT (Insulated Gate Bipolar Transistor): This transistor is a high-performance switch that has the advantages of MOSFETs and bipolar transistors. IGBT transistors are widely used in the fields of power electronics and controllers.