Circuits & Schematics

It’s remarkable how many switching regulator chips use the same basic two-resistor network for output voltage programming. Figure 1 illustrates this feature in a typical (buck type) regulator. See R 1 and R 2 where: Quantitatively, the V ...

Traditionally, the reception quality of a digital receiver is expressed in terms of BER (bit-error rate). This figure is the proportion of received bit errors in a given period. Typically, you measure the BER in the lab by applying an RF signal, ...

This design idea reprises another “1 A, 20 V, PWM controlled current source” ( Ref. 1 ). Like the earlier circuit, this design integrates an LM3x7 adjustable regulator with a PWM DAC to make a programmable 20 V, 1 A current source. It ...

RTDs (resistance-temperature detectors) are the preferred sensor choices for designs requiring precision. Although RTDs are approximately linear over the limited temperature range of 0 to 100 C, these sensors exhibit a slight but progressively more ...

Rheostats Rheostats are simple and ubiquitous circuit elements, usually comprising a potentiometer connected as an adjustable two terminal resistor. The availability of manual pots with resistances spanning ohms to megohms makes the optimum choice ...

This design idea revisits another: “PWM power DAC incorporates an LM317” ( Ref. 1 ). Like the earlier circuit, this one implements a power DAC by integrating an LM317 positive regulator into a mostly passive PWM topology. It exploits ...

This design idea (DI) takes an unusual path to a power-handling DAC by merging an upside-down LM337 regulator with a simple (just one generic chip) PWM circuit to make a 20-V, 1-A current source. It’s suitable for magnet driving, battery ...

Toggle, slide, push-pull, push-push, tactile, rotary, etc. The list of available switch styles goes on and on (and off?). Naturally, as mechanical complexity goes up, so (generally) does price. Hence simpler generally translates to cheaper. Figure ...

The original application of the circuit in Figure 1 was to locate coins, but it applies wherever you need to locate metal objects. The circuit uses a beat-frequency technique: Whenever a metal object comes close to the search coil, the metal causes ...