1. Voltage Difference
The difference in electrical potential between two places.
Unit of measure = V (volts)
Voltage causes current to flow through an electric circuit.

2. Voltage Difference
The voltage difference between the terminals causes charges to move around the circuit.
Energy flows from high to low
Increase voltage = increase in the flow of current.
7.5 PE
9.0 PE

3. Ohm’s Law
The current in a circuit equals the voltage difference divided by the resistance.
I = current (amps, A)
V = voltage difference (volts, V)
R = resistance (Ohms, Ω )

4. Resistance The tendency of a material to oppose the flow of electrons.
The filament in a light bulb is a resistor.
Thicker wire = less resistance
Thinner wire = more resistance
Short wire – less resistance
Long wire – more resistance
Electrical conductors have much less resistance than insulators.

5. Equations
R = V ÷ I
I = V ÷ R
V = I x R

6. Using Ohm’s Law V I R