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 version of Part 1 appeared in the Dec. 2011/Jan. 2012 issue of Test & Measurement World. See the PDF. In January 1979, Electronic Test published an article claiming that a single test circuit that ...

A lot of the analog-circuit conversation these days is centered on low-power and thus low-voltage considerations. That makes sense for operational amplifiers (op amps), of course, since these basic ...

Author Mazi Hosseini describes a simple, low-cost, voltage-controlled current source using two op amps that provides a good range of current and maximum load. One challenge in circuit design is ...

Circuit simulations are great because you can experiment with circuits and make changes with almost no effort. In Circuit VR, we look at circuits using a simulator to do experiments without having to ...

Design analysis of the K2-W Vacuum Tube Op Amp’s design and operation reveals the mad science that created a commercial revolution in 1950s and 1960s analog computing. Op amps played a critical role ...