Using a 4046 PLL this circuit generates rectangular signals in three wavebands that depend on the capacitors used. The circuit is from a Radio Electronics from December 1989.
This circuit was found in a 1962 publication. At the time there were high voltage batteries like the...
Suggested by Sprague in the 1980s documentation, this circuit can control three-phase AC motors....
This circuit divides the frequency of a 2 kHz signal by 2. The circuit was found in Philips...