Conclusion

The basic electrical quantities of Charge, Current, Voltage, Resistance and Power underlie all of the behaviour of electrical and electronic circuits and a thorough understanding of these quantities (and, ultimately, the physical phenomena to which they are related) will help you to comprehend electronics and electricity generally.

   

Vital things to remember

Charge is the number of electrons on or in a body and is measured in Coulombs

1 Coulomb = 6.25 x 1018 electrons or
1 electron charge = 1.6x10-19 Coulombs
} you don't necessarily need to remember the numbers

Current is the flow of charge and is measured in Amps

1 Amp = 1 Coulomb per second

Potential is the force between 2 points that can cause current to flow and is measured in Volts

1 Volt = the potential between 2 points for which a current of 1 Amp will dissipate 1 Joule per second

Power is the energy dissipated per second and is measured in Watts

1 Watt = 1 Volt x 1 Amp

Resistance is the property of a material that resists the flow of current and is measured in Ohms ( W)

1 W = the resistance that allows 1 Amp to flow when 1 Volt is applied

Kirchoff's Voltage Law:

The sum of the voltages around a circuit loop is zero

Kirchoff's Current Law:

The sum of the currents flowing into any point or node of a circuit is zero.