The circuit shown is from Texas Instruments optoelectronics documentation. The input signal is audio and equivalent LEDs can be used. Other operational amplifiers can also be used.
This is another of the Star Trek red alert circuit that you can find on this site. We took this...
Found in American documentation from the 1980s, this circuit is a basic signal rejection filter...
This circuit can be used in physics experiments, in ionization and in several other applications. The...