This circuit is used to detect PLL signals from the 4046 IC. The circuit is from an Electronics Now from October 1994. The indication is made through LEDs.
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...