Old Home
New home of the original useful pages from island.net/~kdbrown.
What's on this side of the tree...
General Electronics stuff:
My ever-popular Canadian Electronics suppliers page, and a growing set of reference material.
Some projects:
I'm not immune to the clock-making habit. Here are a couple of different ones: my Combinatorial Colour Clock (aka the “ish clock”); and my effort to re-design another clock, Sharebrained's Chronulator, to use SMD parts as an alternative to the original through-hole kit design.
Repairs and investigations:
Some reverse engineering and at least one re-interpretation/expansion of published articles.
My Electronics Calculators:
Once I adopted PHP as a general purpose programming language I found myself writing all sorts of utilities to help with the every-day tasks of an Electronics Design Engineer. Many of these have become fairly refined and, at least to myself, quite useful. Some highlights:
- My resistor selector which knows about actual manufactured values and always works within a given tolerance-defined set of parts. It has 5 different modes.
- A dB, peak, peak-to-peak and rms conversion utillity which allows any reasonable conversion in the audio domain. (Some general utility as well.)
- An LED bias resistor calculator that knows about the typical forward voltages of most LED colours, and can handle any number of (same colour) LEDs in series. Since it uses the same routines that the resistor calculator uses, it too knows real resistor values based on tolerance. And it guides the user in consideration of power levels. These aspects are seldom, if ever, considered by the typical on-line LED calculator.
- A utility which calculates evenly—in the ratiometric sense—spaced values given start, stop and number of values to generate. This can be useful in many applications such as LED brightness control and tone generation.
- A PCB track resistance/voltage-drop calculator.
Some specific Web-oriented pages:
This group is a mixed bag of things I've learned along the way when writing these PHP pages.
The star of the show, in my mind at least, is the general triangle solver which uses AJAX to enable all calculations to be performed on the host. It uses my implementation of the method of “interchangeable solutions” which Hewlett Packard calculators often implemented. The code allows any valid combination of sides and angles to be entered, whereby the remaining sides and angles are all calculated. It also accurately draws the solutions, scaled if needed, on a graph-paper style background. It even works, at least in a limited way, with fractions so that woodworkers might find it helpful. (That last capability is new: it did not exist in the original site's version.)