We found this circuit in an old RCA publication. The components are of the time, admitting equivalents. The circuit is triggered in two ways using LDRs.
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...