# What is Voltage?

Voltage is the electrical potential difference caused by the accumulation of electric charges on a point, or a material. If we remove electrons from a material, its total electric charge will be positive.

Remember that we are removing electrons, which are negatively charged, from a neutral atom (which has no charge). This causes the atom is no longer neutral but have a positive charge. We can see that there are 6 protons in the atom (positive charge) and 4 electrons (negative charge). In conclusion, the total charge is positive.

If we increase the amount of electrons in a material, its total electric charge will be negative. We can see that there are 6 protons in the atom (positive charge) and 8 electrons (negative charge). In conclusion, the total electric charge is negative.

If we have two materials with different levels of electric charges, then we say that there is a potential difference between them. To change the electric charge of a material it is necessary to apply energy to the atom. There are several methods for doing this:

• friction
• pressure
• heat
• by magnetism
• by chemical action

When two points having a potential difference are linked through a conductor, it produces an electric current flow. The electric current flows from the point with greatest potential, to the point with lower potential. This is the case of a voltage source.

The potential difference (voltage) is measured in volts (V).

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