American Transistors which are registered with the Electronic Industries Association are assigned a specific number. Each EIA number is comprised of five components.
Japanese Transistors which are registered with the Electronic Industries Association of Japan are assigned a specific number. Each EIAJ number is comprised of five components. An explanation of each component follows :
a) Denotes type of device. Number indicates active electrical connections, plus one.
b) Indicates that the EIAJ or EIA has registered this device.
c) Device application and polarity. (see below)
2N - Transistor, FET, SCR, Triac
2SA - Transistor, high frequency, PNP
2SB - Transistor, low frequency, PNP
2SC - Transistor, high frequency, NPN
2SD - Transistor, low frequency, NPN
2SJ - FET, P channel
2SK - FET, N channel
3SK - MOSFET, N channel
3N - MOSFETS, dual Triacs
$N - OPTO devices
d) EIAJ or EIA reference number. Note: numbers are assigned in order of registration and are not a reliable guide to device specifications, application, or manufacturer.
e) Letter suffix indicates a manufacturer modification to the device (Normally, each successive letter indicates an improvement in specifications. Therefore a "B" suffix would be superior to an "A" or plain suffix device).
Note : Many times an alpha numeric code appears below the part number. This is the manufacturer lot/date code and usually has no bearing on the specification of the device.
Updated August 2, 2010