Circuits & Schematics

Introduction In general, muting and/or signal switching is done by relays, FETs or CMOS analogue switch ICs. All have limitations, but a little known technique that really doesn't look like it could ever work is to use bipolar transistors. The ...

Famous analog designer and author Jim Williams published an awesome design in 1986 for a 100-MHz voltage to frequency converter ( Ref. 1 ). He named this high-climber (picture it on the roof of the Empire State building swatting biplanes out of the ...

In Part 1, we saw how to make an oscillator whose pitch, as opposed to frequency, can be made proportional to a control voltage. In this second part, we’ll look at some alternative ways of arranging things for other possible applications. To ...

If you've ever designed an RF oscillator, you've probably encountered squegging. Sometimes called motor boating, squegging causes oscillators to start and stop at frequencies much lower than the frequency of interest. Viewed on an ...

The recent Design Idea “Getting an audio signal with a THD 0.0002% made easy” [ 1 ] discloses a low THD sine generator which led me to dust off a design that I had published in AudioXpress magazine [ 2 ] (see Figure 1). Figure 1. A ...

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 ...