Working principle and category of crystal diodes 1

There are many types of diodes, which can be divided into germanium diodes (Ge tubes) and silicon diodes (Si tubes) according to the semiconductor materials used. According to their different uses, they can be divided into detection diodes, rectifier diodes, voltage regulator diodes, switching diodes, etc. According to the chip structure, it can be divided into point contact diodes, surface contact diodes, and planar diodes. A point contact diode is made by pressing a very thin metal wire onto a smooth semiconductor chip surface, applying a pulse current to firmly sinter one end of the wire with the chip, forming a "PN junction". Due to its point contact, only small currents (not exceeding tens of milliamps) are allowed to pass through, making it suitable for high-frequency low current circuits such as radio detectors.

The "PN junction" area of surface contact diodes is relatively large, allowing for larger currents (several amps to tens of amps) to pass through. They are mainly used in "rectification" circuits that convert alternating current into direct current.

A planar diode is a specially designed silicon diode that can not only pass large currents, but also has stable and reliable performance. It is commonly used in switching, pulse, and high-frequency circuits.