“If you’ve ever worked with some sort of power electronics or high current devices before, you may have also asked yourself how the current waveform looked in those devices, specially if you were troubleshooting them.
Well, since this is not an unusual topic, there are already a number of commercial solutions. They are called current probes and allow engineers to see and measure current waveforms in an oscilloscope up to tens or hundreds of amps.
Without these devices, it would be very diffficult to work in the power applications field, but they are pricey, though. In fact, the starting price for one of these has surely prevented a lot of people to do it, specially in the hobbyist scene.
There are a huge variety of current probes in the market, everyone built with a different approach in mind. Most of them allow to measure current in a non-invasive way relying in custom magnetic transducers, which stands as the main reason for this things being so expensive.
While this is a very desirable feature, it is very difficult to replicate for the regular maker, since there are no commercially available resources to do it. Therefore, the described current probe in this article uses two terminals and a high bandwidth current transducer IC working in the same way as a multimeter.
This allows for an affordable design which could be easily replicated by the average maker.”