# Semiconductor Device Numbering System | Mystery behind Numbering the Semiconductor Device

0 Semiconductor Devices Numbering System is something that has always piqued the interests of people. Today, let us learn about the mystery behind numbering the semiconductor.

Dear readers, you must have worked at a lab for a university project. As a result, there you might remember using any semiconductor device. Again, while working for an industry also you might have worked using a semiconductor device (Transistor, JFET, MOSFET, Diode, IC). Furthermore, when working with all these devices, you must have caught a glimpse that they have a number printed on their body. Besides, many people must have been curious about the process of this numbering or what is the meaning of it?

## What does it actually mean?

At first, you should keep in mind that semiconductor devices numbering system is not given on a whim. In fact, there are specific principles and regulations that go behind the printing of this numbering. Moreover, the manufacturers adhere to certain policies and do the numbering. As a result, the main objective of today’s article is to brief the numbering system of a semiconductor device simply.

Today, using only 3 steps we will discuss the numbering system of a semiconductor device.

## First step:

Each semiconductor device contains 5 Alpha-Numeric Symbols. So that there are 2 letters and 3 numbers (eg: AF135) or 3 characters and 2 numbers (eg: AFX55).

Likewise, when a semiconductor device has 2 numbers marked on it (e.g. AFX55), then it should be understood as Industrial and Professional Equipment.

Again, when a Semiconductor Device is marked with 3 numbers (eg BF194), then it should be understood that it is Entertainment or Consumer Equipment

## Second step:

Now, the semiconductor device has 5 Alpha-Numeric Symbols. Out of which, there are some Alpha Symbols i.e. English letters in them. Again, the first letter of the English letters indicates the nature of the semiconductor device that means which materiel constitutes the semiconductor device. Here:

• A= germanium
• B= silicon
• C= gallium arsenide
• R= compound material (Cadmium Sulphide)

For example, AE125 is a germanium tunnel diode and BE149 is a silicon tunnel diode.

## Third step:

Among these Alpha Symbols of Semiconductor Device 2nd letter indicates the circuit function of semiconductor device. Here:

• A= diode
• B= variable capacitance diode
• C= A.F. low powered transistor
• D= A.F. power transistor
• E= tunnel diode
• F= H.F. low powered transistor
• G= multiple devices
• H= magnetic sensitive diode
• K= hall-effect device
• L= H.F. power transistor
• M= Hall-effect modulator
• R= thyristor (SCR or Triac)
• S= low power switching transistor
• T= thyristor (power)
• U= power switching transistor
• X= diode, multiplier
• Y= power device
• Z= zener diode

Here, A.F = audio frequency, H.F = high frequency. Now, we will clear the whole topic through two examples.