AC vs electron

AC

noun
  • Companion of the Order of Australia. 

name
  • Aceh, an autonomous province of Indonesia. 

  • Acre, a state of Brazil. 

phrase
  • as charged, as in: guilty as charged, usually a/c. 

electron

noun
  • The subatomic particle having a negative charge and orbiting the nucleus; the flow of electrons in a conductor constitutes electricity. 

How often have the words AC and electron occurred in a corpus of books? (source: Google Ngram Viewer )