And as a former test engineer, I constantly find myself drawn to handy test and measurement equipment for my home lab bench. Recently, on one of my browsing sessions through Tindie, I came across a ground loop detector attachment for Digilent's Analog Discovery 2 (a super handy little USB oscilloscope and logic analyzer).
Ground loops are a tricky subject in the world of analog circuit design. Simply defined, a ground loop happens when there are two different points in a given circuit that are both supposed to be connected to the same ground reference, but instead end up actually having a potential between them for one reason or another. That reason is where ground loop issues get very complex very quickly and can be nearly impossible to find at times.
This handy little attachment for the Analog Discovery 2 works by utilizing its differential input and opening access to it for taking measurements. It also incorporates a low noise differential amplifier for taking very low level measurements as well as detecting ground plane shifts between various ground points in your circuit.
This loop detector has a default gain setting of 100, giving it a bandwidth of 8MHz. This givens you enough speed to measure digital logic as well! Its adjustable low pass filter also allows for you to see what DC effects are happening without too much noise. Overall, it's capable of taking both single-ended and differential measurements at normal voltage ranges and down to 100x's and 1000x's amplification, allowing measurements all the way from 25uV to 250V with 10x probes.
It's easy to take for granted how complex setting up low level differential measurements can get, so having something like this little attachment board with it built in for me is huge. Definitely worth its weight for both professionals and hobbyists alike!