Probing Methods that Boost Power-Conversion Measurement Accuracy (.PDF Download)

Most oscilloscopes ship with 10X attenuation passive probes because this type of probe is well-suited to making measurements across a broad range of applications. These probes are typically rated from dc to 500 MHz and generally can handle up to a few hundred volts. It’s certainly possible to use general-purpose probes for power measurements, but the results will unlikely deliver the level of accuracy needed to drive notable performance improvements in the design. 

The primary goal for power-supply designers and test engineers is to find incremental improvements that will increase power-conversion efficiency or reduce losses in the design. This requires the ability to accurately evaluate and measure very small performance increases. The strategy is that enough small improvements will add up to noteworthy improvements.