Hi, I am trying to verify that a system can run at 50 or 60 Hz and 100 - 240 VAC. Can a Variac be used change both output frequency and voltage or just voltage? Thanks, Jason Mazzotta ...

A variac is usually an auto-transformer, so the output of the variac is still directly connected to the line voltage. The result is that if you touch the output, you're going to get shocked.

"For laboratories currently using Variac transformers to control heat tapes on vacuum chambers, the BC-3 vacuum chamber bake out controller provides a safe alternative to a Variac with additional ...