Circuits & Schematics

A DC load is an essential testing tool for any electronic enthusiast, especially for testing and repairing power supplies. An adjustable DC load can limit the current at any desired level, which makes it suitable to perform various tests because ...

Recently, frequent and favorite contributor Nick Cornford gave us a cool and novel acoustic-interface design for a super sub-ohmmeter capable of audibly sniffing out defects in PWBs: “Tuneful track-tracing” ( Ref. 1 ). Figure 1’s ...

Frequent contributor R. Jayapal recently shared an interesting Design Idea (DI) for power supply control and sequencing in MCU-based applications that combine analog and digital circuitry: “Short push, long push for sequential operation of ...

There are many ways of generating analog sawtooth waveforms with oscillating circuits. Here’s a method that employs a single supply voltage rail to produce a buffered signal whose frequency can be varied over a range from 10 Hz to 1 MHz ...

A topic that has recently drawn a lot of interest (!) and no fewer than four separate design articles (!!) here in Design Ideas, is the conversion of 0 to 20 mA current sources into industrial standard 4 mA to 20 mA current loop signals. ...

A recent Design Idea (DI), “Silly simple precision 0/20 mA to 4/20 mA converter,” ( Ref. 1 ) by prolific DI contributor Stephen Woodward uses the venerable LM337 regulator in a creative configuration along with a few passive components, ...

Whenever you hear the transformerless supply term, you initially imagine the capacitor-based solution: a high-voltage non-polarized capacitor in series with the mains line, a bridge rectifier, a Zener diode, and a filtering electrolytic capacitor. ...

Commercially available IR distance rangers typically handle a 3- to 30-in. detection distance. Many times, it is necessary to determine smaller distances. The circuit in Figure 1 is useful for measuring small distances to reflective surfaces. Its ...

An important figure of merit for all precision constant current sources is their active impedance. Which is to say, just how “constant” is their output held against changes in applied voltage? Frequent and expert Design Idea (DI) ...

Industrial systems normally use both analog and digital circuits. While digital circuits include microcontrollers that operate at 5 VDC, analog circuits operate generally at either 12 or 15 VDC. In some systems, it may be necessary to switch on ...