This circuit was found in an American documentation from the 1980s. The sensitivity ranges from 100 mV to 1 V. The supply must be done with an excellent filtering source.
This circuit was found in an Electronic Design from 1967. The circuit uses two triacs being T2...
Found in old American documentation, this circuit can use crystals between 27.5 and 33 MHz...
This shield from the 60's uses a germanium transistor of the time and a common type of relay of...