Electricity Basics

Electrons & charge

• Electrons
• Electricity is the movement of electrons. 
• Your lightbulb, your stereo, your phone, etc., are all harnessing the movement of the electrons in order to do work.
• Electrons create charge, which we can harness to do work.  

Voltage, current, electric power & electrical energy

• Voltage (V)
• The difference in charge between two points
• The amount of potential energy between two points on a circuit
• Current (A)
• The rate at which charge is flowing
• Electric power (W)
•  The rate, per unit time, at which electrical energy is transferred by an electric circuit. 
• Electrical energy (Wh)
• A form of energy resulting from the flow of electric charge. 
• W * s
• e.g., 1,200W electric appliance used for 2 hours = 2,400Wh = 2.4kWh
• Energy is the ability to do work or apply force to move an object

The water tank analogy

• Analogy
• Water = Charge
• Pressure = Voltage
• Flow = Current
• The more water in the tank, the higher the charge, the more pressure is measured
• Less pressure means less water is flowing

Formula

• W = V * A
• 220V, 4.5A, 990W => 220*4.5=990
• (700W + 1,200W + 1,500W + 800W) / 220V = 19A < 20A
• The breaker will not be working