Identification and detection of crystal diodes 1

A crystal diode, also known as a semiconductor diode or simply a diode, is essentially a PN junction. A lead is drawn from each of the P and N regions, and then packaged in a tube to create a diode. The arrow indicates the direction of current flow. The lead out terminal of zone P is called the positive electrode, and the lead out terminal of zone N is called the negative electrode, with the text symbol VD and graphic symbol.

1. Classification of diodes

According to different manufacturing processes, diodes can be divided into three types: point contact type, surface contact type, and planar type.

According to the material, it can also be divided into silicon tubes and germanium tubes.

According to their purposes, they can be divided into detectors, rectifiers, voltage regulators, light-emitting tubes, and switching tubes.

A crystal diode has low resistance and conducts when subjected to a forward voltage, and high resistance and shuts off when subjected to a reverse voltage, indicating that the crystal diode has unidirectional conductivity.

2. Main parameters of diodes

(1) Maximum rectified current/FNt. The maximum forward average current allowed to pass through a diode during long-term use is called the maximum rectified current, commonly referred to as the rated operating current, which is determined by the PN junction area and heat dissipation conditions.

(2) Maximum reverse operating voltage URM. The maximum reverse voltage specified to ensure the normal operation of a diode without breakdown is often referred to as the rated operating voltage. In general, the maximum reverse operating voltage is about half of the breakdown voltage.diode