Found in an Elektor from the 90s, this circuit is based on components that are still common today. Power is supplied with only two batteries.
This circuit activates a relay that has a lamp as a load. The circuit is from a Radio Electronics from...
This circuit was found in an English publication from1979. The circuit can be assembled with a...
An oscillator whose frequency can be adjusted between 500 Hz and 5 kHz with the use of a...