potency vs voltage

potency

noun
  • Potentiality, ability, capacity. 

  • Concentration; strength 

  • Sexual virility: the ability to become erect or achieve orgasm. 

  • Power, authority. 

  • The ability or capacity to perform something 

voltage

noun
  • The difference in electrostatic potential between two points in space, especially between live and neutral conductors or the earth. 

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