This alarm with automatic shutoff was found in the April 1975 Radio Electronics magazine. The activation time is given by C1 and R3. The alarm uses series and parallel sensors.
This capacitor for small capacitances is based on the tuning of a receiver circuit. The variable is...
This circuit is from the Motorola LinearDatabook of 1990. It shows how it uses the LF355, 356 and...
We found this circuit in an American publication from 1977. Combining a monostable with a...