Potential Difference PDF

# POTENTIAL DIFFERENCE Potential difference, or VOLTAGE, is defined as the difference in electric potential energy per unit charge measured at two points. The unit for voltage is V. The symbol is V. As with the water analogy, voltage can be seen as the energy that each electron has, rather than t...

# POTENTIAL DIFFERENCE Potential difference, or VOLTAGE, is defined as the difference in electric potential energy per unit charge measured at two points. The unit for voltage is V. The symbol is V. As with the water analogy, voltage can be seen as the energy that each electron has, rather than the amount of them like with current. Water on the top of the waterfall stores a lot more energy than the water molecules after they have fallen. You can think of voltage as the energy or "push" on the electrons. Once the electrons return back to the cell, they have lower potential energy than when they left because they went to power some sort of electrical load, which used up some of this energy. The cell (or battery) recharges the energy on the electrons and sends them out again. ## MEASURING POTENTIAL DIFFERENCE (VOLTAGE) A voltmeter is a device designed to measure potential difference. Unlike the ammeter, the voltmeter must be connected in parallel with a load or an energy source. The symbol is a "V" with a circle around it. The reason for this is that voltage is relative to two points. There is always a drop in voltage across a load or energy source. A simple diagram of a voltmeter connected to a light bulb. The voltmeter is connected in parallel with a lightbulb which is connected to a voltage source. The voltage is measured by the voltmeter and shown as a "V". A picture of a voltmeter with a circular gauge. The needle points towards the 20 mark. A picture of a voltmeter with a large rectangular face, the needle is pointing between the 5 and 10 mark.