Another route to signal isolation: Battery powered scopes
A frequent method of examining high-voltage signals is through the use of a battery powered scope which has the advantage of no connections whatsoever to any electrical ground, eliminating possibilities of inadvertent ground loops or something worse. Rohde & Schwarz highlighted its RTH1004 models at its PCIM booth. This is a 350-MHz scope featuring double insolation and CAT IV 600 V/CAT III 1,000 V isolated channels as well as an IP51 housing that meets military requirements. Besides functioning as a scope, it also provides logic analysis, communication protocol analysis, data logging, frequency counting, spectrum and harmonic analysis, and DVM functions. It was hooked up to a demo circuit generating switch-mode supply signals, though obviously it wasn’t reading out circuit parameters when we snapped this picture.