Circuits & Schematics - Oscillators

In the first part ( Ref. 1 ) of this Design Idea (DI), we saw how to use the TDA7052A (or similar) power amp to build a minimalist siren-type power oscillator, and also, having looked at that device’s distortion characteristics under various ...

When audio power amplifiers oscillate, the result is often smoke, perhaps with a well-cooked PCB and a side order of fried tweeter. This two-part Design Idea (DI) shows some interesting ways of (mis-)using a common power amp to produce deliberate ...

One classic set you’ll see in most гvintage mystery movies is an interrogation room with a “two-way” mirror in one wall. This cool gadget lets the witnesses see the suspects from another room while the suspects can see only ...

Frequent contributor Nick Cornford recently shared design ideas incorporating cool circuits for linear-in-pitch voltage-controlled oscillators (LPVCOs): Revealing the infrasonic underworld cheaply: Part 1 ( Ref. 1 ) and Part 2 ( Ref. 2 ) A ...

In Part 1 of this Design Idea [ 1 ], we saw how a standard electret microphone capsule can be persuaded to detect infrasonic signals down to a fraction of a Hertz by adding some fairly simple equalization. In this second and concluding part, we ...

Electrets aren’t only used as audio pickups. For decades, they have been employed in security systems to detect unexpected changes of air pressure within rooms, while more recently they can be found in vapes as suck-sensors (or, more ...

Generating analog sawtooth waveforms (linear ramp followed by a quick reset to zero) from digital timing signals is a common function. It usually requires a negative supply as sketched in Figure 1, where Negative current through R1 ramps up ...

Frequent design idea (DI) contributor Nick Cornford recently published a synergistic pair of DIs “A pitch-linear VCO, part 1: Getting it going” ( Ref. 1 ) and “A pitch-linear VCO, part 2: taking it further” ( Ref. 2 ). The ...

If you've ever designed an RF oscillator, you've probably encountered squegging. Sometimes called motor boating, squegging causes oscillators to start and stop at frequencies much lower than the frequency of interest. Viewed on an ...

The recent Design Idea “Getting an audio signal with a THD 0.0002% made easy” [ 1 ] discloses a low THD sine generator which led me to dust off a design that I had published in AudioXpress magazine [ 2 ] (see Figure 1). Figure 1. A ...