We found this circuit in the October 1996 Electronics Now magazine. The circuit uses LDRs as sensors and drives relays. The relays must have voltages according to the power supply.
The circuit shown here uses a 4047 to produce three signals whose frequencies are determined by C...
We found this circuit in an old English publication. The resistor not indicated can be 2k2 and the...
This circuit was found in documentation from the 1980s. The integrated circuit used is uncommon today...