Photocell night-light study

How it works

A photocell senses ambient light and controls the LED output. Optical feedback matters: if light from the LEDs reaches the photocell, the circuit may switch repeatedly or turn itself off.

The original project uses a transformerless supply, so its nominally low-voltage parts can be at mains potential. The old instructions for modifying a plug and removing its earth pin have been removed from the revised text.

On the bench

Historical reference only; not presented as a build guide. For a new night-light, use an approved isolated low-voltage supply and a redesigned low-voltage sensing circuit. The original photos document the submitted artifact, not approved construction.

Resources & provenance

Rewritten from the original projects/sub/d3mn6sf_prjsub002.php page. Component values and historical performance claims have not been independently bench-tested.