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.
Originally this circuit was indicated to be used in a garage door control, but it can be modified for...
This conventional oscillator with the 741 can be precisely adjusted to produce a 400 Hz signal. The...
This current-limited circuit was found in a Popular Electronics from the 90's. ...