Where does this come from, and can I check it?

The circuit cuts each mains half cycle short so the lamp receives less energy. The figure is taken from International Electrotechnical Commission, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

Is this really a everyday life fact?

Yes. It sits on the Everyday Life shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

What else can I read about it?

The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.

Mondo Knows Facts

A dimmer dims by switching the supply off early

The circuit cuts each mains half cycle short so the lamp receives less energy A simple leading edge dimmer waits part of each half cycle, then fires a triac that conducts until the voltage crosses zero again. The lamp sees a chopped waveform whose average power falls as the delay grows, so it dims. Cheap LEDs often buzz on such dimmers because their drivers expect a smooth supply. It sits in Mondo's everyday life collection, one of 200 facts that each trace back to the reference below.

Where this comes from

International Electrotechnical Commission

Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.

Go further

Technology trivia Science trivia

More facts like this

White LEDs are blue chips coated in phosphorPart of the blue light is converted to yellow, and the mix looks white Incandescent lightbulbs emit mostly heat rather than visible lightOver ninety per cent of electricity consumed by glowing tungsten filaments becomes heat Standard light bulb bases use Thomas Edison's 1909 screw threadCentury-old Edison screw specifications remain global electrical fitting standards USB-C cables use a small pin to negotiate powerA configuration channel settles orientation and how much current may flow AA and AAA battery names are not measurementsThe letters are legacy size labels, and AA is much larger than AAA CR2032 coin cell codes hide diameter and thicknessThe four digits give diameter in millimetres and thickness in tenths

Tags: electricity, lighting, electronics

A dimmer dims by switching the supply off early: the short answers

Where does this come from, and can I check it?: The circuit cuts each mains half cycle short so the lamp receives less energy. The figure is taken from International Electrotechnical Commission, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a everyday life fact?: Yes. It sits on the Everyday Life shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.