Circuits & Schematics - 13

Some circuits need a constant-current source that does not necessarily connect to a power-supply rail or to ground. The circuit in the Figure 1 shows a simple method for achieving that configuration. Figure 1. The simple method achieves a ...

The isolation amplifier circuit of Figure 1 is simple but accurate. With the values shown it converts 0 to 5 V DC or low frequency signals with unity gain, but you can adjust the gain by changing R4. Figure 1. The floating sigma-delta converter U1 ...

Designers often use chargers with flyback topologies to quickly charge energy-storage capacitors (references 1 and 2 ). In a flyback topology, the energy transfer takes place only when the charger’s power MOSFET is off, which effectively ...

Two previous Design Ideas describe simple ways to automatically disconnect a battery from its load after a preset on period, which extends battery life (references 1 and 2). These circuits have little loss in standby operation, but they do draw ...

I was reminded recently of a tester I designed years ago. At the time, I wanted to build “The Ultimate Continuity Tester,” and I established a wish list of all the features I required: A “real continuity” tester. Too many ...

Energy meters, heating/ventilation/air-conditioning (HVAC) systems, and high-power equipments that run on three-phase ac inputs pose a challenge to power-supply designers because nominal input voltage can be as high as 540 V ac. The challenge ...

Low-voltage microcontrollers generally have been powered from a regulated supply, such as 1.8 to .6 V, and have very low current consumption, typically between 1 mA and 5 mA. Achieving an inexpensive, space-saving solution for effective conversion ...

When driving an H-bridge or a similar circuit, you usually must ensure that two or more transistors are not on at the same time. Eliminating multiple transistors from turning on reduces power consumption and lowers EMI (electromagnetic ...

Low-power, low-cost ceramic piezoelectric rate gyros are available, but they lack the low-temperature-coefficient characteristics of their quartz counterparts. However, you can use a servo amplifier to remove the dc level shift due to ...

At least two classic ways exist to address applications requiring sampling of a sum of analog voltages. The most common way is to cascade a classic analog adder and a sample-and-hold amplifier. A classic analog adder is an op amp plus at least ...