01.
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 directly shows the progress of the envelope, it's appropriate to use an analog driver which provides current proportional to the desired light output.…

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02.
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 LEDs work and how to apply them in circuits. Here are some notes on that.LEDs are diodes The first thing to understand about LEDs is that they ar…

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03.
Building a telephone ring booster
2019 Mar 22nd

Building a telephone ring booster

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 paying with my old modem. And that was true, for Internet service. Except for a minor issue of needing to switch my laptop's wireless connection to us…

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