1. Electric Circuits
Chapter 1, Section 3

2. Voltage and Resistance
Current in a circuit increases as
the voltage increases
Current in a circuit decreases as
the resistance increases

3. Ohm’s Law The relationship between voltage, current, and resistance
Current = voltage/resistance
I = V/R
(A) = (V)/(Ω)

4. Circuits
Series Circuit - has only 1 path for electric current to follow
If the path is broken at any point, the current will not flow and the circuit will stop working
The same current flows through all devices connected to a series circuit but the resistance increases with each device

5. Circuits
Parallel Circuit – a circuit that has more than one path for the electric current to flow through
current flows through every path, so if one pathway is broken, it may not affect the others
The current in each path can be different depending on the devices connected to the circuit on that path

6. Protecting Electric Circuits
Circuits are “broken” when the current becomes larger than 15A or 20A
Fuses and Circuit Breakers

7. Power = Current x Voltage
Electric Power
Electric power – the rate at which electric energy is turned into another form of energy
Measured in watts (W)
Power = Current x Voltage
P = I x V
(W) = (A) x (V)

8. Electrical Safety Table 2 on pg 25 – KNOW IT!!
Current as low as .5A (the current needed to power a 60W light bulb) can be deadly to the body

9. Lightning Safety Take shelter if you can see lightning or hear thunder
Avoid high places, open fields, metal surfaces, water, and isolated high objects
Lightning safety position
Squat low on the balls of your feet with your hands on your knees