Light-Emitting Diode

HOW TO RECOGNISE IT

A light-emitting diode is identified by a coloured epoxy dome moulded over two stiff wire legs, lit from a semiconductor junction sealed inside the dome rather than from a filament or an ionised gas. It passes current in one direction only, and the tint of the plastic usually matches the colour it emits, so an unlit one can often be sorted by eye.

MISTAKEN FOR

• Zener Diode
• Photoresistor
• Neon Indicator Lamp