An electrical one way valve-it is a semiconductor device that allows electricity to flow in one direction, but not the other. The symbol is:

Symbol for a diode
Diode picture and symbol. On the left, we see a picture of a diode, with the Anode and Cathode marked, as well as the symbol for a diode. This diode will conduct current in the direction of the triangle in the symbol.


One common use in plant vehicles is in the rectifier of the alternator. The rectifier converts the alternating current produced by the alternator into direct current that can be used by the plant vehicle electrical system.

Electrically, diodes are not 'perfect' components: When they are forward-biased, they suffer from voltage drop, and when they are reverse-biased, they leak small amounts of current.

There are many variations on diodes: Check out LEDs, Schottky diodes and Zener Diodes.

» Course Glossary


Please note, if you want to contact the main Training Centre in Baldoyle, you need to ring 01-8167400.

If you want to contact the CP Fitters' Section, you can Contact Us by email, admin@cpfitters.info, or by telephone: 00 353 1 8167543 This number gets you through to the CP Fitters' Section, Baldoyle Satellite Unit.

Our Address is : Construction Plant Fitters' Section, Unit 116, Grange Way, Baldoyle Industrial Estate, Baldoyle, Dublin D13 CA48.
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