Circle Graphics – Lissajous figures

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.

Beautiful circles with no jagged edges

Making “perfect” circles

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.

Continue reading

BOO!

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!

Continue reading

Transformer Corner

The atmosphere at Oscilloclock.com has been charged lately. Mails have been pouring in from folks who want to generate high voltage for their CRT projects, but have instead ended up with high tension from frustrated attempts. The primary culprit? Lack of a decent HV transformer.

HV Transformer basics

CRTs require high voltage, to coax electrons out of the electron gun and then accelerate them towards their fiery demise at the screen. This voltage can range from hundreds of volts for small tubes, to tens of kilovolts for large tubes! In the case of the Prototype and Model 1 CRTs, around 3kV was needed.

My Oscilloclock needed 3kV to draw this!

Continue reading

The Invisible … Beam?

One of the most exciting things you can do with a Scope Clock is to simply look at it from behind! In many CRTs, the anode coating (a conductive black surface sprayed onto the inside of the glass) doesn’t extend all the way to the screen – leaving a nice gap of clear glass from which to observe the beautiful electron beam.

Ha – you can put down your magnifying glasses now.

Continue reading

Oscilloclock.com site is open!

This site is dedicated to showcasing my Scope Clock designs, and to sharing technical information openly to anyone interested in these vintage electronic timepieces.

What is an “(Oscillo)scope Clock”?

A unique style of clock that displays the time (and other fun things) on a CRT taken from an old oscilloscope. These clocks operate on a fusion of old and new electronics, and are often housed in beautifully crafted cases of wood, metal, or acrylic.

Continue reading