These circuits were found in the February 1995 issue of Electronics Now magazine. The circuits have normal response in (a), boost in (b), cut in (c), and plate response in (d).
This circuit is from a documentation from the 60s. The circuit can be built with transistors like...
Found in a 1966 General Electric documentation, this dimmer should only be used with incandescent...
To control relays safely with double insulation, we suggest the circuit in the figure. The optical...