This circuit was obtained from a 1967 General Electric manual. The circuit makes use of absolutely current components. Similar versions from other sources can be found in this section.
July 2017 - The new Schottky rectifiers from the FMX series for currentes from 1 to 3 A from...
This TTL dice was found in an old American 1980s documentation, but can still be easily assembled....
This circuit uses an operational amplifier to simulate an inductor. The circuit is from old...