Diode, LED and transistor symbols
Semiconductor symbols are almost the same in both standards: a triangle and bar for a diode, with arrows for light, and a base bar with an arrow on the emitter for a bipolar transistor.
SymbolANSI / IEEEIEC 60617What it is
NPN transistorAn NPN bipolar transistor: a small base current controls a larger current from collector to emitter.
Semiconductors: ANSI and IEC
The triangle points in the direction of conventional current, from anode to cathode. On a transistor, the emitter arrow points out for NPN and in for PNP. US drawings often draw a circle round the transistor; IEC drawings usually leave it off.
Frequently asked questions
Which semiconductors appear on a electrical schematic?
This legend covers diode, LED, zener diode, NPN transistor, PNP transistor. Project legends may add more.
Are these symbols different in IEC and ANSI?
2 of the 5 are drawn differently. Each symbol page shows both forms side by side.
Can I download these symbols?
Yes. Each symbol page has free SVG files, and the hub has printable PDF charts.
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