This filter was found in an old publication from 1977. The circuit must use a simple two-voltage source and the components can be changed for operation at other frequencies.
With this circuit, three LEDs of different colors can be controlled sequentially. Adjustments of...
This 1968 Mallory circuit uses an uncommon integrated circuit today. The circuit has a 30 to...
The circuit shown is from an old publication, from the 70s, but can be assembled with TIC106 SCRs...