Electrical gauge (7)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">electrical gauge</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for ammeter that I've seen before include "Current-measurer" , "Measurer of current flow" , "Instrument to measure electric current" , "Electric current measurer" , "Device that measures the flow of electrical current" .)