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Current Shunt Amplifier Module

  1. Oct 31, 2012 #1
    Hello All,

    I'm designing a test setup that requires the use of a 50A 50mV current shunt to take measurements for a circuit which produces pulsed DC currents up to about 100 kHz or so (highest frequency component anyway). I would like to use this shunt here, but also amplify the signal 10x or 100x before feeding it into an oscilloscope.

    I have been searching around online but was wondering if anyone knows of any nifty amplifier modules that are made for use with shunts? I know I could find a shunt IC and roll my own circuit but if there is already a ready-made solution out there, that would be a very good time-saver.

    Jason O
  2. jcsd
  3. Oct 31, 2012 #2
    This sort of thing used to be common in labs under the name bench amp or lab amp or similar.
    Mine still works well after all these years. It has a low frequency point of 1Hz.

    Old fashioned broadband (milli/micro) voltmeters and telecommunications field testing kit often had output terminals as well as input so you could use as an amp.

    You would need to trawl the second hand/surplus outlets to find one.

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    Last edited: Oct 31, 2012
  4. Oct 31, 2012 #3


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    I don't think it would be hard to make a very suitable amplifier with an off the shelf OP amp chip. Are you after a particularly good noise performance?
  5. Oct 31, 2012 #4


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    This sounds like something similar to what is called the transmitter for thermocouples. Probably not a direct fit but it would be a place to start.
  6. Nov 5, 2012 #5
    50mV and 100kHz is nothing special. Make a so-called "instrumentation amplifier" from three op amps.

    Fun: for power meters, one company got a patent to use a copper resistor in the ratio that defines the gain of an op amp. This resistor was coupled thermally with the shunt, so it compensated the temperature drift. Public meanwhile.
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