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Accurately measuring noisy DC

  1. Oct 15, 2007 #1
    Hello All,

    The final segment of my test circuit includes the ability to measure DC (constant or noisy and pulsed) voltage and current. I'm trying to come up with an elegant solution that will give me decently accurate measurements. What I have thought of so far is to use a high value resistor to measure the voltage and a shunt to measure current, but i'm not sure what kind of IC to use to accurately get the votlage and current values.

    Most of the stuff I play with generates lots of funny waveforms that aren't anywhere near clean so I'm wondering if I whould use an RMS to DC converter chip to integrate all the noisy stuff and then feed that into a DAC. But if I use one of those chips, do they also measure the DC component as well? I've never really delved into this area so I'm not sure what IC or apparach would be best. So far, the best resource I have found is this link here:


    But there are so many options to choose from. Would anyone happen to have some advice for me on this?

    Thank you,
    Jason O
  2. jcsd
  3. Oct 16, 2007 #2

    I think I've decided to simplify the setup by just making a circuit to measure the voltage alone. For this idea, I am thinking about using a simple resistor divider with a small filter cap in parallel with the input to an ADC to smooth out some of the spikes.

    Now my question is about any possible concerns that may come up here. I am designing this circuit to take input voltages up to 1000VDC (very overrated for what I am expecting but adding this for a safety margin). At that voltage, is there anything I need to look out for when choosing the right resistors? I know that I at least need to use a filter cap that will handle 1000V.

    Jason O
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