Units of Charge

Electrical charge is nothing more than a group of electrons.  There are several units that are used to quantify the number of electrons.  

ELEMENTARY CHARGE/ELECTRON CHARGE (e)
This is the electrical charge of a single electron.

In the water analogy, the elemental charge is similar to a molecule of water.

COULOMB (C)
This is the unit of charge used in electronics, and most other sciences.  This unit is one of the most important units in electronics because this is what ties other electrical units to other fields of science. The definition of the coulomb is what insures that a watt of electrical power is the same as a watt of heat power.

The quantity of a coulomb was first estimated by Charles-Augustin de Coulomb as 6.241509074x10¹⁸ electrons.

The coulomb's symbol is "C" 

There are several other units of charge, but these are the ones most used in electronics.  As time permits, I will add more units of charge below.

In the water analogy, the coulomb is like a gallon of water.

ABCOULOMB (abC) / ELECTROMAGNETIC UNITS (EMU)
The abC and EMU are both equivalent to each other and are equivalent to 10 coulombs of charge. This exact scale of 10 comes form the fact that the abcoulomb and the coulomb were defined in similar terms, just using different units.  The difference in the units used amounts to a factor of 10.

The term "abcoulomb" is a contraction for "absolute coulomb."

FRANKLIN (Fr ) / STATCOULOMB (stC) / ELECTROSTATIC UNITS (ESU)
The Fr, stC and ESU are all equivalent to each other.  These are defined in terms of a static charge.  

The term "statcoulomb" is a contraction for "static coulomb."

The coulomb is defined in terms of a flowing charge.  For this reason, one C is equivalent to 2,997,924,580 stC.  If that number looks somewhat familiar, that is because it is 10 times the speed of light.  This makes some sense because electrons move at the speed of light.  Also notice that the abC is 10 coulombs. 

PLANCK (qp)
I will work on this more in the future, but it is related to calculating the amount of charge a black hole can contain.

Planck formulated a system of natural units that is a very interesting read. 

FARADAY (Frs) (Not to be confused with a farad, which is the SI unit of capacitance)
This is a unit of charge that fits nicely into chemistry.  It is essentially the charge of one mole of electrons.  A faraday of charge is about 96,500 coulombs of charge.