This circuit was found in General Electric's 1965 documentation. It appears elsewhere on the site. The SCR and the diodes must be in accordance with the motor current.
This circuit was obtained from an English magazine from 1977. The magazine no longer exists, but...
This 45 to 90 Hz hum elimination circuit was obtained from a 1980s documentation. The operational can...
This circuit produces 1 kHz square signals using the CMOS IC 4070. The frequency is given by the...