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, or PCB (printed-circuit-board) traces...
Circuit controls inrush current in ac-operated power supplies
5 octave linear(ish)-in-pitch power VCO
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...
Sensing and power-generation circuits for a batteryless mobile PM2.5 monitoring system
Particulate matter (PM2.5) monitoring is a key public-health metric. Vehicle- and drone-mounted sensors can expand coverage, but many existing systems are too costly for broad deployment...
Tune 555 frequency over 4 decades
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...
Measure resistance and temperature with a sound card
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...
Littelfuse expands magnetic sensor portfolio with ultra-low-power omnipolar TMR switches
Littelfuse, Inc. announced the launch of two next-generation omnipolar magnetic switches, the LF21173TMR and LF21177TMR. These devices combine Tunneling Magnetoresistance and CMOS technologies in a compact LGA4 package...
Charge coupled MOSFET relay
This circuit acts as an AC/DC relay with a rating up to 50 volts peak and up to 10 Amps of current...
Combine two TL431 regulators to make versatile current mirror
Various designs for current mirror circuits have been an active topic recently here in Design Ideas. Usually, the mirror designer’s aim is to make the mirror’s input and output currents accurately equal, but Figure 1 shows one that takes a tangent...
FM receiver/radio using Arduino and TEA5767
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...
Ignoring the regulator's reference redux
Stephen Woodward’s “Ignoring the regulator’s reference” Design Ideas is an excellent, working example of how to include a circuit in the feedback loop of an op amp to support the stabilization of the circuit’s operating point...