Weird Oscillation in wheatstone bridge circuit

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epcole
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I have this weird oscillation coming from my circuit. its a wheatstone bridge with a single strain gage. I am using The PST 4130 from Omega Engineering to supply +10vdc. When I first turn it on the signal is pretty clean, but after a while, it turns into this:

[PLAIN]http://www.hiboox.com/go/pictures/computing/export,1e27b7fa699b1d58cdd55d0891f17ce1.jpg.html
link:
http://www.hiboox.com/go/pictures/computing/export,1e27b7fa699b1d58cdd55d0891f17ce1.jpg.html"

I'm using 120ohm resistors. The noise shows up at about every .002sec and oscillate at about 100khz.
Does anyone have an idea what this is and how to get rid of it? It is really throwing off my calculations.
 
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  • Green oscillograph-style plot of V3 against V1 with four dense bursts of noise spaced evenly along the x-axis, sitting above a steadier noisy baseline near -0.044.
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Last edited by a moderator:
Sounds like noise from a switched mode power supply.

For a $180 10 watt power supply which is claimed to be low noise, this one isn't very good.

If it is still under warranty, you could call the suppliers and get it fixed. In any case, call them and see what happens.