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 takes advantage of the inductance of the coil of a high-impedance phone to form the...
This circuit controls a fan in the car, according to the temperature, activating it automatically when the...
In relation to the previous circuit (CB18493E) this spy has an extra transistor, which can be a...