二极管的分类（Classification of diodes）.docVIP

二极管的分类（Classification of diodes） (1) classification of semiconductor materials by use The semiconductor materials used by diodes can be divided into germanium (Ge) diodes, silicon diodes and GaAs diodes (GaAs) and phosphating gallium (GaP) diodes. (2) classification by structure Semiconductor diodes are mainly based on PN junction. The point contact type and schottky type which are indivisible with PN junction are also included in the general diode range. Including these two models, according to the characteristics of the PN structure, the crystal diode is classified as follows: 1. Point contact diode The point contact diode is formed by pressing a metal needle on a single chip of germanium or silicon and then through the current method. Therefore, the PN junction has a small electrostatic capacity and is suitable for high frequency circuits. However, compared with the face type, the point-contact diode is both characteristic and reverse, so it is not possible to use large current and rectifier. Its cheap because its simple. For the general purpose of small signal detection, rectification, modulation, mixing and limiting, it is a wide range of applications. 2. Key diode Key diodes are formed by welding or silver filaments on a single wafer of germanium or silicon. Its characteristics are between point contact diodes and alloy diodes. Compared with the point contact type, although the PN junction capacity of the keyed diode increases slightly, the forward characteristic is especially good. Multiple switching applications, sometimes applied to detection and power supply rectifier (no more than 50mA). In bonding diodes, the diodes of the fused wire are sometimes called the gold bond, and the diodes of the fused wire are sometimes referred to as the silver bond. 3. Alloy diode In a single chip of N type germanium or silicon, the PN junction is formed by means of alloy indium, aluminum and other metals. Small forward voltage, suitable for large current rectifier. It is