Found in a 1970s documentation, this mini-organ toy circuit makes use of an integrated circuit from that time. This component is difficult to obtain today.
This is a possible setting for a Colpitts oscillator operating in the audio track. The shunt coil...
We found this circuit in documentation from the 1950s. The circuit basically applies to germanium...
This excellent 3-transistor audio preamplifier is suitable for use with high-impedance...