Bulb repeatedly lit with current suppressed (5)
I believe the answer is:
onion
'bulb' is the definition.
(plant bulb)
'repeatedly lit with current suppressed' is the wordplay.
'repeatedly' indicates the doubling of some letters.
'lit' becomes 'on' (eg a light that is switched on).
'with current' becomes 'i' (symbol for electric current. I am not sure about the 'with' bit.).
'suppressed' is an insertion indicator (inserted letters are suppressed by others).
'on' duplicated is 'onon'.
'onon' enclosing 'i' is 'ONION'.
Can you help me to learn more?
(Other definitions for onion that I've seen before include "Edible tear-jerker" , "veggie" , "The tear-inducing vegetable" , "Pungent vegetable" , "Shape of Russian dome" .)