Pro Electron system of semiconductor labelling and Range numbers.

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Pro Electron system of semiconductor labelling

The Pro Electron system of semiconductor labelling, used by most European manufacturers, describes a device by means of a code comprising two letters and a serial number. Letters define the semiconductor material used and the device’s general function:

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Serial numbers define the device’s particular application and consist of either: three numbers (which shows the device is intended for use primarily in consumer applications) or; a letter followed by two numbers (which shows the device is intended for use primarily in industrial or professional environments).

Range numbers

Where variants of a device exist, the above code is addended with a further code (separated by a hyphen) to identify the specific device type within the range. Two classes of device are affected:
(a) Rectifier diodes and thyristors; figures indicate either the repetitive peak inverse voltage, VRRM, or the repetitive peak off-state voltage, VDRM, whichever is the lowest.
(b) Voltage regulator diodes and transient suppression diodes; a first letter (voltage regulator diodes only) indicates operating voltage tolerance, where: A = ± 1%; B = ± 2%; C = ± 5%; D = ± 10%; E = ±15% and a group of figures indicates the typical operating voltage (or the maximum recommended stand-off voltage, in the case of transient suppressor diodes).
In all cases, a final letter (R) may be used, to indicate a reverse polarity version (i.e. one with a stud anode).

Abbreviations and symbols

Many abbreviations are found as either capital or lower case letters, depending on publishers’ styles. Symbols should generally be standard, as shown.

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Letter symbols by unit name

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