Circuits & Schematics

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) ...

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 ...

A few months back, frequent DI contributor Nick Cornford showed us some clever circuits using the TDA7052A audio amplifier as a power oscillator. His designs also demonstrate the utility of the 7052’s nifty DC antilog gain control input: ...

The versatility of the venerable LMC555 CMOS analog timer is so well known it’s virtually a cliche, but sometimes it can still surprise us. The circuit in Figure 1 is an example. In it a single linear pot in a simple RC network sets the ...

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 ...

Circuit analysis Figure 1 shows the schematic diagram of the device. As it is clear, the circuit consists of 3 main parts: Arduino-Nano (Controller), FM receiver module, and the audio amplifier. Figure 1. Schematic diagram of the digital FM ...

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 ...

Unless you add a measurement instrument to your computer, you have only the sound card as an analog I/O port. You can use the sound card to digitize ac analog voltages but only within a limited range. You can, however, add some signal processing ...