EMF is a DC voltage present even in an open circuit, when no current is drawn. EMF comes from a cell/battery or DC generator. EMF is the cause; potential difference is the effect.
But potential difference exists when there's no current drawn too. That's just more confusion.
One aspect I'd noticed is that EMF doesn't necessarily have a corresponding potential difference. Eg. a generator with the output short-circuited still has the same EMF as if it was open circuit but potential difference is zero or near-zero across any two points in its windings or circuit.
One aspect I'd noticed is that EMF doesn't necessarily have a corresponding potential difference. Eg. a generator with the output short-circuited still has the same EMF as if it was open circuit but potential difference is zero or near-zero across any two points in its windings or circuit.