Question

Voltages are always measured between two point.why?

Answer 1

Explanation:

because its has a starting source and a ending point

Answer 2

A voltage causes a current to flow through “something” (usually to do some kind of work, generate heat, etc). In order to “flow through” you need a physical place for current to go “IN” to something and another physical place for current to come “OUT” of that same something. Two points, and the amount of current is completely dependent upon how hard it (that current) has to be pushed to move between those two points.