Found in Popular Electronics from the 90s, this 1.5 A power supply can supply voltages selected by a switch. The splitter resistors determine the output steps.
This circuit was found in a documentation by A. Fanzeres making use of a grounded metal housing...
This circuit, found in a Popular Electronics from 1992, is based on an oscillator and a crystal...
This amplifier for small cassette tape players was found in an English documentation from 1969. The...