In short, [Christer] needed a high-frequency active differential oscilloscope probe, and they’re not cheap. So he built one himself. With some minor tweaking on the input damping resistors ...

A differential probe, a device for measuring the voltage between two points in a ... and the power is derived from the scope’s USB interface. All in all it’s an extremely well-executed device ...

Oscilloscope probes have a specified operating bandwidth and, in some cases, built-in switchable attenuators. Differential probes are used to measure differential ... polarity probes, continuity ...