Found in Unitrode documentation, this oscillator uses some unusual components today such as PU and the 3 M potentiometer. The power can be made with voltages around 15 V.
This efficient filter against EMI has several coils, being L1 and L2 formed by 100 turns of wire...
This optical sensor circuit for a robot was found in the March 1986 issue of Radio Electronics magazine....
This circuit can provide both positive and negative voltage outputs from 2 to 12 V with current up to...