Circuits & Schematics - Supply

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 ...

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 ...

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. ...

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 ...

Large power supplies that operate from ac wall voltage have large input-filter capacitors. You must limit the inrush current to those capacitors. Otherwise, the supply may trip the ac circuit breaker, or you may damage the rectifier, filer chokes, ...

The circuit in this Design Idea detects short-circuit faults or excess-current conditions in line-operated equipment, such as a UPS (uninterruptible power supply), across an isolation boundary. If the load current rises higher than a predetermined ...

This circuit acts as an AC/DC relay with a rating up to 50 volts peak and up to 10 Amps of current. The differential oscillator supplies voltage to the gates of the two FETs with good isolation will drawing only 1.5 mA of current. Materials on the ...

Various designs for current mirror circuits have been an active topic recently here in Design Ideas (DIs). Usually, the mirror designer’s aim is to make the mirror’s input and output currents accurately equal, but Figure 1 shows one ...

Stephen Woodward’s “Ignoring the regulator’s reference” ( Ref. 1 ) Design Ideas (DI) (see Figure 1) is an excellent, working example of how to include a circuit in the feedback loop of an op amp to support the stabilization ...