ABSTRACT
Perhaps it would be wise at this stage to revise potential difference (p.d.). A p.d. is exactly what it says it is: a difference in potential (volts). Hence two conductors having p.d.’s of, say, 20 and 26 V have a p.d. between them of 26 20 6 V. The original p.d.’s, that is, 20 and 26 V, are the p.d.’s between 20 and 0 V and 26 and 0 V.
