This alarm circuit was found in April 1975 Radio Electronics magazine. The circuit uses a 12 V power supply and relay but can be modified to work with other voltages.
Found in a Raytheon circuit manual from the 1960s, this circuit uses the CK722 and a...
With this circuit it is possible to measure RF signals with a common multimeter. Signals up to 200...
This circuit was found in a 1967 US publication. In it we have the implementation of a ring...