Definition
An electronic circuit or device that changes the timing relationship (phase) between an input alternating-current signal and its output, without changing the signal's frequency. In aviation electronics, phase shifters are used in instruments and radio systems where two signals must be compared or combined at a specific phase relationship to produce correct readings or directional information.
Plain English
A small circuit that delays or advances an electrical signal so it lines up correctly with another signal. The signal still wiggles at the same speed, but its peaks and troughs are nudged forward or back in time.
Context Anchor
Seen in aircraft electrical and electronic system discussions, especially where instruments, radios, or control circuits compare one signal with another.
Derivation
From Greek 'phasis' meaning 'appearance' or 'stage,' used in physics for the position of a wave in its cycle. A phase shifter literally shifts where the wave is in that cycle.
Why Pilots Care
Many navigation instruments work by comparing the phase of two signals. If a phase shifter fails or drifts, course needles, bearing pointers, or autopilot inputs can give wrong readings.
Analogy
Think of two flashing lights that are supposed to blink together. A phase shifter is like a timing adjustment that makes one light blink a little earlier or later than the other.
Intuition Check
Do not read “phase” here as a stage of a project or flight. In this term, “phase” means the timing position of a repeating electrical signal.
Example Sentence 1
The technician traced the bearing error to a faulty phase shifter in the VOR receiver.
Example Sentence 2
During the preflight check of the navigation equipment, the phase shifter corrected the timing offset between the received signals.