Definition
A transformer in an aircraft electrical system used to step alternating current (AC) voltage up or down to the level required by a particular piece of equipment. It transfers electrical energy from one circuit to another through electromagnetic induction between two coils of wire wound on a common iron core, without any direct electrical connection between the two circuits.
Plain English
A device that takes incoming AC electricity and changes it to a higher or lower voltage so a piece of equipment gets the voltage it needs to work properly.
Context Anchor
Seen in aircraft electrical-system descriptions, wiring diagrams, and maintenance manuals, especially where equipment needs a different voltage from the aircraft power source.
Derivation
From Latin 'transformare,' meaning 'to change shape.' The device 'transforms' electrical power from one voltage level to another. 'Power' here distinguishes it from small signal transformers used inside electronic circuits — a power transformer handles the supply voltage that runs the equipment.
Why Pilots Care
Maintains correct voltage for radios, instruments, and other critical systems; failure can cause loss of electrical power to essential equipment.
Intuition Check
Power here means electrical power, not engine power. A power transformer changes electrical voltage; it does not create power or increase engine output.
Example Sentence 1
The radio's internal power transformer steps the 115-volt AC bus voltage down to the lower voltages needed by its electronic circuits.
Example Sentence 2
During the preflight, the pilot noted the power transformer was supplying stable voltage to the navigation lights.