[sdiy] oscilloscope art

[Roy J. Tellason]

On Monday 25 April 2005 03:51 pm, Fernando de Izuzquiza wrote:
> found this right now
>
> http://www.crowncity.net/ratcave/Electro/ScopeArt/ScopeArt.html
>
> not new but maybe some new data on it.
>
> How to create the + and - 45 degree phase shift?
> With a dome filter? With a phaser stage?
>
> Enjoy. Best wishes to all,
>
> Fernando

I used to have a number of fairly early cheap (~$20!) tube scopes that I 
picked up secondhand,  here and there.  I had some fun with some of them by 
taking an old (tube-type) audio output transformer and wiring it in reverse,  
with the "speaker" leads serving as the input and the "primary" having one of 
the wires going to the horizontal input and one going to the vertical input.  
Then I'd connect a capacitor (probably around 47nF if my memery serves) 
across one of the inputs,  to ground.

It produced some interesting patterns,  considering how simple that setup was.