This circuit is from the Motorola Linear Databook of 1990 and can be implemented with other operational amplifiers. The power supply must be symmetrical.
This circuit turns a relay on or off by touching the sensors or by connecting sensors at these...
This circuit is from a 90s Popular Electronics. It consists of a power source for bass amplifiers...
This circuit is from 1990 documentation. It uses a bridge with LEDs and the potentiometer must be...