The most common and most likely answer to this crossword clue is the 3 letter word AMP
I've seen this crossword clue in Financial Times
A
M
P
More clues leading to the result AMP
- Strip lights to give some electricity
- A legislator's current measure
- Measure of current in uncovered light source
- American legislator’s current measure
- A rather quiet sound is increased by this
- A moderately quiet form of electronic equipment
- Physics unit within campus
- Physicist restricted, having had wings clipped
- Current 27 confirmed as President
- Unit needed for electric guitar?
Buddy explains!

The straight part
We know that "Measure of current" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case measure of current = amp.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does AMP mean?
AMP noun- Short for ampere.
- Short for amplifier.
- Short for ampoule.
- Short for amputee.
- Short for ampicillin.
- (usually with up) To amplify.
- (usually with up) To excite.
- (usually with up) To intensify or increase.