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.
This circuit was found in an English publication from 1989. The integrated circuit is an...
This circuit was obtained from a 1964 magazine and has some interesting features such as the input...
Using a general-purpose transistor this AC amplifier was found in the November 1993 issue of...