What do the terms potential difference, electromotive force, and voltage have in common with each other?

Question

I've seen all three terms, and they all have units of Volts. I'm wondering about how they are alike and how they are not, besides having units of Volts, of course.

Answer 1

They all mean "voltage", pure and simple.

There are some subtle differences, but you can ignore them for all practical use. I've been an engineer for 30 years and I've never used them.

But to be specific, potential difference is just the voltage between two points, that is, the voltage.

electromotive force is the voltage generated by a battery or other source, that is, the voltage.

.

Answer 2

They are all similar to 'Pressure Difference'. (PD or ΔP) in that, in electricity, the PD, EMF and V all cause the flow of electricity in a circuit as with the flow of fluids in a pipeline which requires a PD (Pressure difference) in order to flow.

Answer 3

its all in Physics in closed and open circuits

Answer 4

Voltage is a general term and can be applied to both DC and AC circuits in simple terms it is the push or pressure that pushes electrons around a circuit.  Electromotive force emf is generally used to describe the voltage of an electrical source such as a battery or series of batteries

potential difference is used to describe the difference in voltage between 2 points in a circuit that occurs when current is flowing in that circuit. To summarise  

Voltage is a general term for electrical pressure

EMF is used to describe voltage sources

PD is the difference in voltage between 2 points in a circuit

Example please draw this simple circuit

A circuit consits of 2 x 6 ohm resistors connected in series to a 12 volt battery.

The battery EMF is 12 Volts

The current = I = V/R= 12/12 = 1 amp

Voltage across resistor 1 = V1 = Current x R1 = 6 Volts

Voltage across resistor 2 = V2 = Current x R2 = 6 Volts

The PD between the positve terminal and the mid point of the circuit is 6 Volts

The PD btween the negative terminal and the mid point is 6 Volts