Circuits & Schematics - 5

Included among the many applications for pulse-width modulation (PWM) are voltage regulation, power-level control, and fan-speed control. A PWM circuit for such systems can be implemented with three op amps on a single quad-op-amp chip (Fig. 1). ...

High speed and precision are not the only areas where special V-F circuits are needed. Figure 1 shows a circuit which runs from a single 1.5 V cell with only 125 µA current drain. The circuit uses an LT1017 dual micropower comparator in a ...

Systems using line receivers for differential input signals require an adequate self-test capability. Using an LM339 (a quad differential comparator), you can provide this capability by constructing the configuration shown in the Figure 1. ...

The gain temperature coefficient of conventional V-F circuits is affected by drift in the charge pumping capacitors. Although compensation schemes are employed to minimize the effect of this drift, another approach is required to get significantly ...

Manufacturers of optocouplers characterize their devices for CTR (current-transfer ratio), and an optocoupler’s data sheet will list its CTR ranges. Unfortunately, the CTR range may be too wide for some applications, requiring you to screen ...

Few methods for analog to digital conversion are more “mature” than the classic combination of a voltage-to-frequency converter (VFC) with a counter. VFC digitization is naturally integrating, so good noise rejection is inherent, as is ...

This circuit of only a few components is powered by two AA batteries and features a mode that extends its power savings. Imagine a smart light switch which not only automatically turns itself on when it gets dark, but also adjusts its level of ...

It’s interesting, useful, and fun that basic electronic topologies often turn out to have utility in multiple and surprisingly different applications. Figure 1 shows an example of such a circuit. It’s a charge pump voltage inverter ...

This Design Idea mates a precision current source IC with precision difference amp chips to create a programmable current source or sink. The resistor-programmable current source/sink in Figure 1 illustrates the basic topology, taking advantage of ...

In many applications, there are requirements of low power, high performance differential amplifiers to convert small differential signals to a readable ground referenced output signal. Input voltages at two inputs usually share a large common-mode ...