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.
With this circuit it is possible to control a current of several amps, depending on Q1, from a low...
Programmable unijunction transistors are not commonly used components today. This Popular...
This circuit has a waveform adjustment made with a potentiometer. C1 and R1 determine the base...