This simple two-transistor FM transmitter was found in the November 1991 issue of Radio Electronics magazine. The circuit has a 2 + 2 turn coil of 28-gauge wire with a diameter of 1 cm.
This old slide projector control circuit was found in an 80s Hands On. The circuit uses modern...
In the figure we have a circuit that uses unusual components, being indicated for low frequency...
The sensor of this circuit found in Popular Electronics can be formed by a piece of fabric between two...