Navigation:: Home >> Electronic components >> this page

Transistor and diode numbering systems

- the Pro-electron and JEDEC numbering systems for semiconductors

Bipolar transistors tutorial includes:

• Transistor basics
• Transistor numbering codes
• Transistor datasheet parameters

There are two main numbering systems for semiconductor diodes, transistors and FETs. One numbering or code system is used more widely in Europe and the other in the USA. The European based system is known as the Pro-electron (Proelectron) system, and the one used more widely in North America is the JEDEC system.

The numbers using the Pro-electron and JEDEC systems have different formats as seen below:

Pro-Electron Numbering or Coding System

First Letter Specifies semiconductor material	Second Letter Specifies type of device	Subsequent Characters
A = Germanium B = Silicon C = Gallium Arsenide R = Compound materials	A = Diode - low power or signal B = Diode - variable capacitance C = Transistor - audio frequency, low power D = Transistor - audio frequency, power E = Tunnel diode F = Transistor - high frequency, low power G = Miscellaneous devices H = Diode - sensitive to magnetism L = Transistor - high frequency, power N = Photocoupler P = Light detector Q = Light emitter R = Switching device, low power, e.g. thyristor, diac, unijunction S = Transistor - switching low power T = Switching device, low power, e.g. thyristor, triac U = Transistor - switching, power W = Surface acoustic wave device X = Diode multiplier Y = Diode rectifying Z = Diode - voltage reference	The characters following the first two letters form the serial number of the device. Those intended for domestic use have three numbers, but those intended for commercial or industrial use have letter followed by two numbers, i.e. A10 - Z99.

From this it can be seen that a BC109 is a low power audio transistor and a BBY13 is variable capacitance diode for industrial or commercial use.

JEDEC Numbering or Coding System

First Number	Second Letter	Subsequent numbers
1 = Diode 2 = Bipolar transistor 3 = FET	N	Serial number of device

Thus a 1N914 is a diode and a 2N706 is a transistor.

By Ian Poole

<< Previous | Next >>

Further pages from this tutorial
Page [ 1 ] >> [ 2 ] >> [ 3 ] >>