We found this circuit for receiving shortwave on a mediumwave radio in a 1986 Hobbyst Electronics PE. The circuit has the received band given by T1 which can be an FM IF.
This compact power supply can be used on the workbench for up to 1 A load. The transformer has 1 A secondary...
This circuit found in old documentation is based on the 709 which is an operational amplifier that...
This circuit uses a capacitor to store energy. The capacitor is charged by closing S1 by a moment. Them,...