We found this circuit in a Maxim documentation from the 90s. The 4-channel circuit uses a component of the time and has a supply current of only 6 uA.
This circuit was found in old American documentation. Transistor is general purpose and relay is...
This simple alarm with latching uses a relay as the main element. The circuit is from a Radio...
This circuit is from an Italian publication called Fare Elettronica from 1987. What we have is an...