Normally, if you want to control the gain of an amplifier, you’ll use a variable resistor. You know, like a volume control. But what if you want to control the amplifier’s gain with a voltage?

A question that arises frequently in audio and signal processing applications is this: How can I control gain on dual channel (e.g., stereo) inputs simultaneously with only a single knob? Of course, ...

Members can download the PDF ebook. One day, back about 1966, I was going up the elevator at 285 Columbus Avenue in Boston to look at some production problems on Philbrick’s fifth floor. And who was ...