This circuit for the 60 kHz range was found in 73 magazine and published in 1995. The circuit uses a ferrite rod. Note the direction of the coil windings.
This circuit with 1% regulation aims at replacing mercury cells. We found it in a 1967...
This transistor tester configuration can be found on this website with many variations. The...
This high current control circuit was found in a publication from the 1990s. The power transistor must...