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

Click For Summary

Discussion Overview

The discussion revolves around the search for ready-made amplifier modules suitable for amplifying signals from a 50A 50mV current shunt, particularly for applications involving pulsed DC currents at frequencies up to 100 kHz. Participants explore various options, including existing laboratory equipment and potential DIY solutions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant, Jason O, is looking for ready-made amplifier modules specifically designed for use with current shunts to amplify signals before feeding them into an oscilloscope.
  • Another participant mentions that bench amplifiers or lab amplifiers used to be common and suggests searching second-hand outlets for such equipment.
  • A different participant proposes that creating an amplifier using an off-the-shelf operational amplifier (OP amp) chip would not be difficult and questions whether high noise performance is a requirement.
  • Another contribution suggests that the application might be similar to transmitters used for thermocouples, indicating a potential starting point for further exploration.
  • One participant notes that the specifications of 50mV and 100kHz are not particularly challenging and suggests building an instrumentation amplifier using three op amps. They also mention a patented method involving a copper resistor for temperature drift compensation in power meters.

Areas of Agreement / Disagreement

Participants express a range of views on the availability and construction of amplifiers, with some suggesting existing solutions while others propose DIY approaches. There is no consensus on a specific ready-made solution, and the discussion remains open-ended.

Contextual Notes

Some assumptions about noise performance and specific application requirements are not fully explored, and the discussion does not resolve the practicality of the proposed solutions.

Jdo300
Messages
548
Reaction score
5
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
 
Engineering news on Phys.org
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.
 

Attachments

  • benchamp.jpg
    benchamp.jpg
    34.9 KB · Views: 551
Last edited:
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.
 

Similar threads

What is the best method for wideband current measurement?
  • · Replies 7 ·
Replies
7
Views
4K
How Can You Measure Noisy DC Voltage and Current Accurately?
  • · Replies 1 ·
Replies
1
Views
3K
Audio/Video Troubleshooting a DIY Music System: Amplifier Issues
  • · Replies 27 ·
Replies
27
Views
6K