To dim a light on AC, why is a choke (coil) better than a resistor?
A resistor would limit the current but waste the extra energy as heat.
A resistor would limit the current but waste the extra energy as heat. A choke is an inductor: it limits AC current through its reactance XL = ωL, but because its voltage and current are 90° out of phase, it consumes almost no average power (it stores and returns energy each cycle). So a choke controls the current while staying cool — far more efficient than a resistor.
Key point
An inductive choke limits AC current with near-zero power loss (voltage and current 90° out of phase).
Common mistake
thinking a choke wastes power like a resistor.
Memory tip
choke limits AC current without heating up — resistors burn the excess.
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