Fancy measurement gear is often expensive to buy, but some bits of kit are entirely DIY’able if you’re ... frequency active differential oscilloscope probe, and they’re not cheap.

Utilize analog and digital signal processing techniques in building a low-cost high-precision digital oscilloscope for high school use.

The oscilloscope photo below shows this changing ... which are reasonable values for a meter. DIY HV probe resistors waxed For R1 I purchased 25 200MΩ high voltage resistors (MX440-200M, 1% ...