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