This circuit can be used in a signal level indicator with LEDs. The circuit is from an Electronics Now dated January 1996. The power supply must be dual.
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...