The Collaborative International Dictionary
Step-up \Step"-up`\, a. (Elec.) Transforming or converting a low-voltage current into one of high voltage; as, a step-up transformer.
Wiktionary
a. 1 That increases in stages 2 (context of a transformer etc English) That increases a voltage
WordNet
Usage examples of "step-up".
For an increasingly larger portion of humanity, such places are now not just home but the end of the rainbow: the ultimate step-up from a zinc-roofed shack in a shantytown.
He hauled one huge step-up transformer before him, adjusted a complex array of coils and dials.
There was a sharp, whirring sound, and crackling sparks shot from the step-up transformer.
The trickle of power flowed into superconductor cables, becoming a stream of electricity that was boosted with a step-up transformer into a raging torrent of power that was converted into safe and harmless microwaves to beam down to Earth.