Definition
An electronic circuit that converts an alternating current (AC) input into a direct current (DC) output whose voltage is approximately twice the peak value of the AC input. It uses a combination of diodes and capacitors to charge on one half of the AC cycle and add to that charge on the next half, producing a doubled output.
Plain English
A small circuit that takes an AC voltage and produces a DC voltage about twice as high. It does this by storing energy in capacitors during one part of the AC cycle and adding more during the next part.
Context Anchor
Seen in aircraft electrical and avionics maintenance when discussing power-supply circuits inside equipment, rather than as a normal cockpit operating item.
Derivation
From 'voltage' (electrical pressure) and 'doubler' (something that doubles). The name describes exactly what the circuit does: it doubles the voltage. The plain name is accurate, so no deeper origin is needed.
Why Pilots Care
Allows instruments and radios to receive the higher voltage they need from a lower-voltage aircraft electrical system without adding heavy transformers.
Intuition Check
A voltage doubler does not double the total electrical power available. It raises voltage, usually with less available current and some loss.
Example Sentence 1
The instrument's power supply uses a voltage doubler to produce the higher DC level needed by its display circuits.
Example Sentence 2
A failed voltage doubler can cause intermittent radio dropouts during flight.