This 10-minute timer was found in the July 1994 Radio Electronics magazine. The relay must be sensitive to the supply voltage used. The capacitors determine time ranges.
This digital CMOS circuit generates sinusoidal signals from a 10 kHz rectangular signal. The...
Found in an 80's Elektor, this circuit can use any equivalent optical coupler. The buzzer is of the...
Found in a 1965 Electronic Design, this circuit limits surges in a load when power is applied. The...