This circuit was found in a 90s Popular Electronics. With it, using a 4066, it is possible to control between 1 to 100 the gain of an operational amplifier like the 741.
We found this circuit in a 1991s PE Hobbyst Handbook. The circuit fires 10 LEDs that can control...
The circuit shown is an amplifier for medium impedance headphones including bass and treble...
In a voltage follower the voltage gain is unity. The input impedance is high and the output...