Alternate title: "This Dad put -10V into a TL074 and here's what happened to his liver!"Most everybody knows that it's a bad idea to bring the inputs of the common TL074 op amp to a voltage more negative than about 4V above the negative power rai…
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Q: The analog synth circuit I'm building calls in the schematic for ferrite beads on the power rails, but it doesn't give any further information. What kind of beads should I use? A: Pick some that will look nice on the board, maybe in a co…
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Testing and adjustment are often underestimated in DIY circuit design. It's all very well to choose exactly the right topology and component values for a circuit; but even with a perfect design on paper or in the simulator, how does one get from…
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When I draw the first draft of a new circuit design, I'll usually work out the topology of the circuit first, and leave out any component values unless it's instantly obvious what they need to be. The topology means which components exist a…
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In the last entry I described the electrical requirements of LEDs and how to drive them in the context of analog circuitry. When you want to indicate information with the brightness level of a single LED, as in my Transistor ADSR where the LED dir…
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Light-emitting diodes! They're all over our electronic equipment; but what are they all about, really? The underlying concepts are simple, but there are a lot of frequently-asked questions that show there's confusion among hobbyists about how…
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I recently switched to a new cable Internet modem, because the cable company (which provides my home Internet service) assured me that the package that came with the new modem would be cheaper for the same service compared to what I'd been payi…
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I'm sometimes asked about the environmental consequences of modular synthesizers. It's an interesting question with a lot of ramifications, and there's a lot of misinformation circulated. That may be inevitable given the nature of this busine…
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Exponential converters are basic building blocks used in many synth circuits, but for many of us, they are incomprehensible black boxes. The basic concept of how an exponential converter works is very simple; but the simplest possible circui…
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In my last entry I talked about the rules for simplifying series and parallel circuits. Two resistors in series can be replaced by one with a value equivalent to the pair of them; two in parallel can similarly be replaced; there are other rules…
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When I started breadboarding the Coiler VCF (see my new videos about it...), I ran into a problem: the design called for a couple of 6800pF (also known as 6.8nF) capacitors, and I didn't have any of those on hand. I didn't want to rush out and…
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One of the most common beginner SDIY questions is which parts are frequently used and worth buying in large quantities to use on multiple projects. The people who ask this question think they're going to save serious amounts of money by buyi…
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