This circuit was obtained in a 1968 manual of General Electric. The components used are of the time, but they admit equivalent. Observe the optical feedback system for control.
This circuit was found in the October 1989 issue of Radio Electronics magazine. It drives an...
This interesting configuration was found in a 1965s Electronic Design. It makes use of components of...
This interesting bandpass filter using an operational amplifier 741 has its cutoff frequency...