In this circuit of an old American documentation, the input impedance is the same as the output impedance. The circuit has a sensitivity of 1 Vpp at 75 ohms.
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...