This circuit is from an 80's Electronic Engineering. The base is a common operating and 4 single integrated voltage comparators. The circuit directly drives 4 indicator LEDs.
This is a high voltage probe that allows the measurement of high continuous voltages with a common...
The circuit shown in figure is suggested by Texas Instruments (www.ti.com) and makes use of the...
This well-known configuration of the guitar effects pedal was obtained in an English magazine from...