This is the traditional voltage follower configuration with the 741 operational amplifier. The circuit is from 1976 documentation and the power supply must be symmetrical from 6 to 15 V.
This circuit controls two lamps so that when one increases in brightness the other decreases. The...
We found this circuit in an Argentine documentation from 1973. The transistor admits a more modern...
This circuit was obtained from a 1998s Popular Electronics. The magazine no longer exists, but the...