What do diode numbers mean

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Viewed 95 times. NickT NickT 13 2 2 bronze badges. Add a comment. The third letter does not have any particular significance. The letter is used to mention the specialized application of the diode. But 4N and 5N are only used for optocouplers. The sequential numbers run from to and indicate the approximate time the device was first made. For example, a 2NA is an enhanced version of a 2N It has higher gain, frequency, and voltage ratings.

Always check the datasheet. Examples: 1N, 1N diode and 2N, 2N transistors. These part numbers take the form: digit, two letters, sequential number, [optional suffix] Digits are 1 for diodes, 2 for transistors, and so forth. The letters indicate the type and intended application of the device according to the following code.

SE — Diodes. SF — Thyristors. SH — UJT. SM — Triac. SQ — LED. SR — Rectifier. SS — Signal diode. ST — Avalanche diode. SV — Varicap. SZ — Zener diode. If any suffix presents then for this suffix Always check the datasheet because it represents various things.

Note the polarity. Much like a battery, a diode has a polarity. The negative side, or cathode, is usually represented by a bar, band or line along one end of the component body. It may also be marked with a "K" or by a raised or tapered edge.

The positive side, or anode, typically has no marking. Decode the diode type and material designation. This is designated by the "1N" in the part number. The "1" identifies the component as a diode.