IPA: //ˈdaʊblər//
KK: /ˈdaʊblər/
A device that increases the frequency or voltage of a signal to twice its original value.
The engineer used a doubler to enhance the signal strength in the circuit.
Doubler → It is formed from "double" (from Old French *dobler*, meaning to make double or to fold) and "-er" (meaning a person who). A doubler is a person or thing that makes something double or increases it.
Think of someone who 'makes something double' — that's what a doubler does.