Using 4 tubes, this 1924 receiver combines new technologies as an intermediate frequency stage that was already beginning to appear. Listening is via phone and battery power.
This circuit found in a French documentation from 1982 can be applied to any operator. The...
In this circuit of the 1980s, the T1 transformer has 30 turns of 28 primary wire and the secondary...
Found in American documentation from the 90s, this circuit triggers a buzzer with a Sonalert-type...