Circuits & Schematics

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, ...

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 ...

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 ...

The LM358 family of dual op amps is among those hoary industry work-horse devices that are inexpensive and still have their uses. These parts’ outputs can approach (and for the inputs even include) their negative supply rail voltage. ...

Recently, frequent Design Idea (DI) author Christopher Paul showcased an innovative and high performance true-two-wire current source using a depletion mode MOSFET as the pass device in “A precision, voltage-compliant current source” ( ...