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 circuit, suggested by National Semiconductor, decodes audio signals from stereo TV...
Found in a 1970 documentation, this circuit makes use of 741 operational amplifiers that are...
Suggested by General Electric in 1967 documentation this circuit uses an isolation transformer to...