Are There Ready-Made Amplifier Modules for 50A 50mV Current Shunts?

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SUMMARY

This discussion focuses on the need for amplifier modules suitable for a 50A 50mV current shunt in a test setup designed to measure pulsed DC currents up to 100 kHz. Users suggest utilizing old bench amplifiers or lab amps, which are still effective for this purpose. Additionally, creating a custom solution using an off-the-shelf operational amplifier (op-amp) is recommended, specifically by constructing an instrumentation amplifier with three op-amps for optimal noise performance. The conversation highlights the availability of second-hand equipment and the potential for innovative designs using thermal compensation techniques.

PREREQUISITES
  • Understanding of current shunt principles and specifications
  • Familiarity with operational amplifiers (op-amps) and their configurations
  • Knowledge of instrumentation amplifiers and their applications
  • Basic experience with oscilloscope measurements and signal amplification
NEXT STEPS
  • Research available bench amplifiers or lab amplifiers for current shunt applications
  • Learn how to design and build an instrumentation amplifier using op-amps
  • Explore thermal compensation techniques for amplifiers to minimize temperature drift
  • Investigate second-hand electronics markets for surplus amplifier modules
USEFUL FOR

Electronics engineers, test equipment designers, and hobbyists working with current measurement systems and signal amplification techniques.

Jdo300
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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.

Thanks,
Jason O
 
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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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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?
 
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.
 
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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