Without regulation, this basic circuit has the output current, and voltage determined by the transformer. The input can be 110 V and 220 V if the transformer used is of the indicated type.
This circuit is from 1989 documentation. It uses the TDA2002 as a modulator and the unusual power...
This configuration is suggested by Mullard (Philips) in an old manual of 555 integrated circuits....
The figure shows how to use a CMOS amplifier as a crystal-controlled oscillator. The circuit is...