Solar flashlight (CB20488E)

This circuit charges a battery to power a flashlight at night. The circuit is from an English publication from 1991.

Simple 60 Second Timer (CB12419E)
This timer was found in a 1994 Electronics Now. The relay must be a sensitive type. If it has a...
Oscillator with Relay (CB19779E)
We can make an oscillating relay producing a rectangular signal taking advantage of the inductance of...
White Noise Generator (CB17603E)
This circuit appears at various points in this section and on this site, with minor variations. It uses the...