The most common and most likely answer to this crossword clue is the 7 letter word AMMETER
I've seen this crossword clue in The Daily Telegraph
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M
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More clues leading to the result AMMETER
- It shows level of current temperature after girl turns up on English river
- It goes with the flow
- Measuring device encountered in more than half of America
- It measures the flow of the current
- The setter’s put in a dodgy term for current device
- It makes current measures possible
- It measures current in the morning and energy used in new term
- One reflecting the current situation had an audience in the morning with the Queen
- . Measuring instrument found in possession of Gurugram meterologist
- Instrument for measuring current and amplitude modulation encountered base resistance
Buddy explains!

The straight part
We know that "It makes current measures possible" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case it makes current measures possible = ammeter.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 AMMETER mean?
AMMETER noun- A device that measures the magnitude of an electric current, especially one calibrated in amperes.