The most common and most likely answer to this crossword clue is the 9 letter word REPEATERS
I've seen this crossword clue in The Times
R
E
P
E
A
T
E
R
S
Buddy explains!
The straight part
We know that "Electrical devices" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case electrical devices = repeaters.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 REPEATERS mean?
REPEATERS noun- One who or that which repeats.
- A student repeating a course or class.
- A patient who repeatedly presents with the same symptoms.
- A consumer who repeatedly purchases the same goods or services.
- One who votes more than once at an election.
- In ufology and similar studies, a person who regularly sees unexplained sightings of paranormal phenomena.
- A gun that has a store of cartridges and does not need reloading after each shot.
- A telegraphic instrument for automatically retransmitting a message.
- An electronic device that receives a weak or low-level signal and retransmits it at a higher level or higher power.
- A watch with a striking apparatus which, upon pressure of a spring, will indicate the time, usually in hours and quarters.
- A frigate appointed to attend an admiral in a fleet, and to repeat the admiral's signals.
- A pennant used to indicate that a certain flag in a hoist of signal is duplicated.
- A repeating decimal.
- In calico printing, a design repeated at equal intervals in a pattern.