This simple circuit is a continuity test that, in addition to testing resistors, can also test other components. Power is provided by batteries and the LED can be of any color.
The circuit presented was found in the 1994 National Instruments Linear Applications Handbook and...
We found this circuit in a 70's RCA manual. The circuit provides 0.5 W power in the 700 MHz to 1...
This old circuit uses two light-sensitive SCRs or LASCRs. The circuit drives small loads. The...