This shortwave preselector was found in the July 1994 issue of Radio Electronics magazine. The circuit is suitable for telescopic antennas, matching the impedance with the receiver used.
This old oscillator using germanium transistors has a high impedance headphone as inductor to...
This old fashioned amplifier can source some watts to a low impedance loudspeaker. The circuit...
This 50 Hz rejector or notch filter was found in a 1975 documentation. Other frequencies can be...