# What is meant by protons having positive charge?

I am really confused in physics with my course chapter "Electrostatics". So I used google to search for my answers but I'm not satisfied with them.

What is the meaning of a proton having positive charge? Does that mean protons are tiny particles having more protons than electrons? Is that why protons have positive charge?

My professor wrote down this definition of charge:

There is no particular definition of charge but its the property by which electrons and protons attract each other.

• proton has more protons than electrons? – Shing Oct 19 '16 at 11:20

When physicists created the sources of electricity, they called one pole positive and the other negative. They decided that electric charges move from the positive pole to the negative pole. Then it turned out (later on) that the electrons move in the opposite direction, so the electrons are charged negatively, according to the previous convention. The protons are the charged positively, and in electrolytes they indeed move from the positive pole to the negative one. Historically it was so, and the main thing to keep in mind is that the electron and the proton have charges of the opposite sign.

A simple (but essential, mathematical) answer might be as follows. Dirac by deriving his equation from the relation: $$E=±(m_0^2c^4-p^2c^2)^{1/2}$$ (which formally defines the relativistic expression for the energy)

showed that the minus sign in this relation implies the existence of anti-particle with an opposite charge sign (than the particle). On this basis, when we have electrons with negative charges (we should have positrons with positive charges), when we have anti-protons with negative charge (then we also have protons with positive charges) and so on. So, the existence of two different particles with opposite charge signs (such as electrons and protons) is quite natural and logical in mathematical point of view!