This is a simple voltage tester for voltages from about 2V to about 15V with the indicated resistor and red LEDs.
This circuit can be used as an input shield by removing the signal directly from the second port,...
This sensitive circuit was found in an Electronics Hobbyists Handbook from the 1990s. The circuit can...
We found this circuit in an 80's documentation. The circuit has a gain of 30 dB and uses a varicap...