Definition
The frequency of the small alternating-current variation that remains on the output of a direct-current power supply after rectification and filtering. In a typical aircraft DC system fed by a rectified AC source, the ripple frequency is a multiple of the input AC frequency determined by the rectifier circuit (for example, twice the input frequency in a full-wave single-phase rectifier).
Plain English
When AC power is converted to DC, the result is not perfectly smooth — a small wave still rides on top of the DC. Ripple frequency is how many times per second that leftover wave repeats.
Context Anchor
Seen in aircraft electrical-system discussions, especially when checking alternator output, charging-system health, or unwanted electrical noise in radios and instruments.
Derivation
Ripple comes from the image of small waves on the surface of water — here, small voltage waves left on top of an otherwise steady DC output. Frequency simply means how often those waves repeat per second.
Why Pilots Care
Excessive ripple can interfere with sensitive avionics and indicate failing diodes or poor electrical system health.
Analogy
A steady electrical supply is like a smooth road. Ripple is the small repeated bump, and ripple frequency is how often those bumps come along.
Intuition Check
Ripple frequency is not the size of the ripple. It means how often the ripple repeats.
Example Sentence 1
The technician measured the ripple frequency on the DC bus to verify the transformer-rectifier unit was filtering correctly.
Example Sentence 2
A sudden increase in ripple frequency warned the crew of a diode failure in the alternator.