Handcrafted Scope Clocks with circle graphics
In Transformer Corner Part 3, I looked at how to choose materials for a custom HV transformer. One way was to pull stuff from the junk-box – I did this in my early Prototype. The much, much better way was to use an off-the-shelf core with documented specs.
Let’s look at winding up the transformer. It’s amazingly easy to get a workable result!
In Transformer Corner Part 2, I looked at the power supply used in my early Prototype, and showed how to determine the key requirements for the HV transformer.
Now, let’s see how I could choose the materials and design the transformer – without any pesky mathematical formulae!
The first challenge was to find a suitable core from my junk box. First off, recall from Part 1 that this couldn’t be iron (too ‘slow’ for 151 kHz), and it couldn’t be air (too ‘weak’ for 25mA). I suppose I could have tried plastic, milk, or even beer – but I knew better. I knew about a substance called Ferrite.
(more…)In Transformer Corner part 1, I introduced one of the key parts of the Oscilloclock – the HV transformer, and tried to illustrate some of the concepts and history behind it.
Next, let’s explore the Prototype’s power supply configuration. This will tell us a lot more about the transformer I had to wind!
My greedy little Oscilloclock wanted lots of different voltages…
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By the time you read this post, you must have seen the term “Circle Graphics” in a thousand places across the site.
In fact, “Circle Graphics” is not an official term – I just use it to describe how shapes are drawn on these clocks:
Everything you see on this screen is made up of CIRCLES! Blank out part of a circle and you get an arc. Squish an arc and you get a line. This clock simply draws circles, lines, and arcs of different sizes at various points around the screen. It does it quickly. And it does it very, very well!
The effect of using circles is beautiful – shapes are smooth and precise, with no jagged edges or pixelation.
I carry on as if it were some incredible new concept or discovery, like the Higgs boson. But in fact, the analog technique of constructing perfect circles, ovals, and lines on a CRT is very, very old. These figures are really part of a class of shapes called Lissajous Figures.
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Oscilloclock.com proudly presents a new feature – Seasonal Treats !
This month, the ghosts come out of the attic and merge with the electron stream, leaving their telltale prints in the phosphor… but if you get too scared? Just push the button and blow them up!
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