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Scope bath

Immerse circuit and view voltages
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I build prototype circuit bits mainly "in the air" without the support of a perforated board. In the event that it does not work, circuit nodes have to be probed under power to make sure that the voltages are in the vicinity of what I expect them to be. Sometimes this causes grief as the multimeter or CRO probe shorts out adjacent nodes and sets a load of silicon free of its magic smoke.

I propose a tub filled with a liquid with electro-optically active (kerr effect*) liquid, illuminated by a xenon strobe thorough a polariser, viewed through polarising glasses. The circuit is put in, clocked at x Hz and the strobe run at x + .05 Hz. Voltage changes in each wire will be visible as a change in its colour, slowed down to once per 20 seconds.

* Kerr Effect: Under the action of an electric field, certain fluids change their optical properties, viz: transmission, dispersion, or rotation of polarisation.

neelandan, Dec 24 2001

Magic Smoke (in ICs) http://www.science....n/m/magicsmoke.html
[bristolz, Dec 24 2001, last modified Oct 17 2004]

Bob's Breadboarding ideas http://www.planetee...ment?ArticleID=1706
What is all this breadboarding stuff, anyhow? [neelandan, Dec 24 2001, last modified Oct 17 2004]

[link]






       Liquid instumentation! Cool idea. Do you think that such a liquid would alter the behavior of the circuit under inspection?
bristolz, Dec 24 2001
  

       Wouldn't the liquid effectively be putting a (high-ish?) resistance between all of the exposed wire in the circuit? This doesn't seem like a good idea if the circuit is running at a high frequency.
cp, Dec 24 2001
  

       I thought this was going to be about bathing in mouthwash.
TeaTotal, Dec 24 2001
  

       Not all liquids conduct electricity. WD-40 doesn't...I've sprayed it into a moldy ignition switch to clean things up before...
StarChaser, Dec 24 2001
  

       Seems like there'd be a problem of range as well. Would you be able to tell the difference between 4 VDC and 4.5 VDC (if it makes a difference)? And would the same substance work for 500 VAC?   

       If you don't want to breadboard, try a quasi breadboard with cardboard and tacks. Or use stiffer wire for your prototypes.
phoenix, Dec 24 2001
  

       I had a stovetop element burn halfway through over t-giving, there was a pop and no one could figure the source until I happened to look to the white glow coming from under a pot. *Bright* white, I should add. Had I poured water on the pot to put out a boilover …   

       On topic: I like this idea, but it hearkens to much IC processing I know of that is baked. Last neat idea about optically active fluids I saw involved the reproduction of 3D topography in optically active resin. Could an IC surface map be reproduced by activating a IC submerged in optically reactive resin?
reensure, Dec 24 2001
  

       [bristolz]: the liquid might add some capacitance to the circuit; I do not think any effect would be appreciable.   

       [cp]: most kerr effect liquids seem to be insulators.   

       UB: teeth?   

       [PeterSealy]: missed you, on a first cursory look, because the annotation did not have the customary beginning. The board is needed to support components so that the assembled circuit can be carried about. Without a board, the circuit cannot be moved off the table without something shorting out.   

       [phoenix]: try larger separation for larger voltages so that the resulting electric field is about the same. And no, you might not be able to distinguish a change of 10%.   

       [reensure] : Is that reproducing hills and vales using resin, or making voltages visible?   

       [Rods Tiger]: right, on all counts.
neelandan, Jan 04 2002
  

       There's a real-world version: if you put an IC chip under a scanning electron microscope and tune the energy just right, then voltages on the chip surface will appear as black/white changes in the image of the chip. If you clock a microprocessor really slowly, you can see the signals moving through the whole device.
wbeaty, Oct 01 2003
  
      
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