This circuit was obtained in a documentation from the 70s. The operational amplifiers used are uncommon today. Modern equivalent types can be tried out.
Suggested by Sprague in the 90's documentation, this circuit applies to AC motors. The...
We found this circuit in Electronics Now magazine from December 1995. Any operational amplifier can be...
This circuit was found in Sgnetics documentation from the 80's. The circuit also has loudness...