"A **coulomb** is the amount of charge that passes a point through a wire carrying one ampere for one second. Voltage is a measure of electrical potential energy in units of volts or** joules per coulomb** (energy/charge). Then 1 volt means 1 **joule per coulomb**; 2 volts mean 2 **joules per coulomb**, and 5 volts mean 5 **joules per coulomb**." Discussion

"It does seem like a strange combination of units, doesn't it? A **coulomb** is a quantity of electrical charge. As an analogy, I'm going to use a gallon (or litre if you're an SI person) as a quantity of water. I can lift the water and give it gravitational potential energy. The higher I lift, the more gravitational potential energy it has. Thus, the joules per gallon (energy per unit volume) varies depending on how high I lift the water. The same goes for voltage, which is **joules per coulomb** (energy per unit charge): the higher I "lift" the charge (i.e., the higher the voltage), the more potential energy it has." Discussion

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