Diode Coding

Diode Coding :-

First letter - Semiconductor material


 * A Germanium
 * B Silicone
 * C Gallium arsenide, ect.
 * D Photodiodes, ect.

Second letter - Application


 * A General-purpose diode
 * B Variable-capacitance diode
 * E Tunnel diode
 * P Photodiode
 * Q Light emmiting diode
 * T Controlled rectifier
 * X Varactor diode
 * Y Power rectifier
 * Z Zener diode

Third letter - In case of diodes for specialized applications, the third letter does not generally have any particular significance.

Zener diodes - have an additional letter after the numbers denoting the tollerance :-


 * +/- 1%
 * +/- 2%
 * +/- 5%
 * +/- 10%

Zener diodes also have additional characters which indicate the zener vltage e.g. 9V1 indicates 9.1V