The diode model is divided into five parts (the fifth part is also omitted), as shown in Figure 5-7.
The first part: Domestic diodes use the number "2" to indicate that they are mainly called diodes. Imported ones use "1" for diodes and "2" for triodes.
Part 2: Use letters to indicate the material and polarity of the diode (A means germanium N type, B means germanium P
Type, C represents silicon N type, D represents silicon P type)
The third part: use letters to indicate the type of diode (P for ordinary type, V for mixing detection
Tube, W means voltage regulator tube, Z means rectifier tube, L means rectifier stack, S means tunnel tube, N means damper tube, U means photosensitive tube).
Part 4: Use numbers to indicate serial numbers.
Part Five: Use letters to indicate the specification number of the diode.
For example, the model of a certain diode is 2AP9. Among them, "2" means diode, "A" means
N-type germanium material, "P" stands for ordinary type, and "9" stands for serial number.
At present, many imported diodes are used. The diodes whose model number starts with "1N" are American nomenclature, such as 1N4007: those whose model starts with "1s" are Japanese nomenclature, such as 1S1885.