The versatile phase-locked loop (PLL) allows multiplication of a reference frequency with an operating frequency that ranges from “DC to daylight.” A PLL is overkill for some applications, however, ...

Charging a supercapacitor from a 5V USB port may seem simple at first, but to charge three supercapacitors to 7V and to limit the input current to the 500 mA maximum limit on the USB port is somewhat ...

An autotransformer is a transformer having part of its winding included in both the input and output circuit. A simple autotransformer connection is shown in Fig. 1. Note that because there is a ...

Last time on Circuit VR, we looked at creating a very simple common emitter amplifier, but we didn’t talk about how to select the capacitor values, or much about why we wanted them. We are going to ...

Sometimes a circuit requires a data link over an existing cable that doesn’t have any free conductors for a dedicated comm link. A common solution is to superimpose a high-frequency carrier modulated ...