Based on the LF256 operational amplifier, this circuit was found in the September 1989 issue of Radio Electronics magazine. The indicator is analog, and the power supply must be symmetrical.
This circuit was found in an American documentation from the 80's. The components are from that...
The circuit shown is from the Texas Instruments optoelectronics manual. It is intended for audio...
This circuit drive an LED with constant current determined by the values of the resistors of 10...