North Coast News

How to choose component values
2019 Jul 28th

How to choose component values

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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Driving LEDs digitally
2019 Apr 15th

Driving LEDs digitally

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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LEDs and analog drivers for them
2019 Apr 8th

LEDs and analog drivers for them

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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Exponential converters and how they work
2018 Oct 12th

Exponential converters and how they work

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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Combining components for new values
2018 Sep 19th

Combining components for new values

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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Common parts to keep in stock
2018 Aug 23rd

Common parts to keep in stock

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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Transistors for the Perplexed
2018 Jul 8th

Transistors for the Perplexed

Most transistor circuits are quite straightforward.  If you look at the schematic of something like the North Coast Transistor Mixer, you can easily recognize common patterns - an emitter follower here, a common-emitter amplifier there - w…

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State of the store
2018 Jun 8th

State of the store

In the last couple weeks, since the storefront move, I've been busy with a lot of store and non-store issues and haven't had much time to update here.  Sorry about that; here are some notes on what's going on. Storefront This Web site is s…

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One minute op amp analysis
2018 Mar 11th

One minute op amp analysis

You can understand most op amp circuits with just three simple rules. If, through negative feedback, the op amp can bring its inputs to equal voltage, then it will do so. Otherwise, it will drive its output near whichever power supply voltage co…

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Voltage control modifications
2018 Feb 25th

Voltage control modifications

There's a recurring thread that comes up again and again in SDIY fora, where someone asks how to "mod" an existing device that is not voltage-controlled to give it a CV input. Sometimes this question is asked in relation to a specific product, in wh…

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