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 was found in a 2000 Poptronics. The magazine no longer exists, but the circuit can be...
This 80's circuit has an input resistance of the order of 880 M and gain 10, using operational...
This circuit can be used in a toy organ. The frequencies are determined by the capacitors selected by...