Resistor
Fixed resistor, measured in ohms (Ω)
A resistor is a small part that limits how much current flows in a circuit.
Its value is shown by coloured bands (red-red-brown = 220 Ω) and its size tells you how much heat it can handle, usually ¼ W.
Resistors have no direction: they work either way round.
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Everything on this subject: Resistors, Simplified