Electronics > Projects, Designs, and Technical Stuff

Measuring PWM current?

<< < (3/3)

BravoV:

--- Quote from: oPossum on April 29, 2019, 04:42:50 am ---Range?
Resolution?
Accuracy?
Average, min, max, RMS, peak to peak?

--- End quote ---

Another important one ... frequency, its a nasty little devil of it's own imo.

ogden:

--- Quote from: iXod on April 28, 2019, 09:16:11 pm ---For a PWM voltage, is using a shunt and observing voltage with oscilloscope the only way to get even a ballpark current measurement?

--- End quote ---

Other option would be to use current clamp-on probe. One shown below have slow low bandwidth (20KHz), yet it is considered as low cost and may do the job in the "ballpark" category. Obviously there are >= 1MHz BW clamps, but for a price.

https://www.picotech.com/accessories/current-probes-clamps/60-a-current-probe-bnc

Dave have video regarding scope current probes:

https://youtu.be/kmCvrGVtC0M?t=1

OM222O:
he says "scope gives accurate RMS measurments" as if somehow the scope is doing something magical ... ANY half decent RMS to DC converter with enough bandwidth should be plenty good enough for this application.

Jeroen3:
Your DMM should have no problem with PWM current. Unless you PWM at 5 hz or something ridiculous low.
RMS might be off a bit, since part of the waveform is beyond it's bandwidth.

Some multimeters can even do PWM voltage from VFD's, with an extra low pass. (Fluke 87v for example)

David Hess:
An oscilloscope with AC/DC current probe is the most universal method and can work to multiple MHz.  A current shunt can be used with an oscilloscope and differential probe.  At low frequencies, other ways are feasible like using a multimeter.

Navigation

[0] Message Index

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod