1. Electric Circuits
Chapter 20.3

2. Key Concepts and Vocabulary
What is included in a circuit diagram?
How do series and parallel circuits differ?
How do you calculate electric power and electrical energy used?
Vocabulary:
Electric circuit
Series circuit
Parallel circuit
Electric power

3. Circuit Diagrams Use symbols to represent parts of a circuit. Include:
Sources of electrical energy
Devices that are run by electrical energy

4. Circuit Symbols
Each battery = 1.5V

5. Types of Circuits

6. Series Circuits Charge has only ONE path through which it can flow.
If one element stops functioning in a series circuit, NONE of the elements can operate.
The bulbs in a circuit are a source of resistance. The more bulbs, the more resistance.

7. Objects in Series - 6V 3V 0V +
Voltage is split equally among the resistors in the circuit.
Current is the same throughout the circuit.

8. Draw a diagram for this circuit
What would the voltage be at each bulb if the total voltage is 9 V.
How could you make each bulb brighter

9. Parallel Circuit
Charge has TWO OR MORE paths through which the charge can flow.
If one element stops functioning, the rest of the elements can still operate.

10. Lamps in Parallel

11. Draw a Circuit Diagram

12. Draw a Circuit Diagram

13. Which is a series circuit and which is parallel circuit?

14. In which are the lamps in series and in which in parallel?

15. Power and Energy Calculations

16. Power
Power is the rate of doing work.
Power is measured in WATTS (W).

17. Electrical Power
Electrical power is the rate at which electrical energy is converted to another form of energy.
Electrical power is calculated by multiplying voltage by current.
P (watts) = I (amps) x V (volts)

18. Electrical Power
Electrical power is calculated by multiplying voltage by current.
Power (P) = Current (I) x Voltage (V)
(W)atts (A)mps (V)olts

19. Practice Problem P = I x V P = 34A x 240 V P = 8200 W
An electrical oven is connected to a 240-volt line, and it uses 34 amps of current. What is the power used by the oven?
P = I x V
P = 34A x 240 V
P = 8200 W

20. Math Practice Practice Problems Page 611 Page 613 Problems 1 – 3

21. Electrical Energy How much energy is used by an appliance.
Energy = Power x Time
E = P x t
Unit = kilowatt-hours

22. The power rating on an electric oven is 9300 watts
The power rating on an electric oven is 9300 watts. If the oven is plugged into a 240-volt line, how much current does it use? What is the resistance of the oven? If the oven is operated for 1 hour per day, how much electrical energy does it use per day.

23. A freezer has a power rating of 105 watts
A freezer has a power rating of 105 watts. How much current does it use if it is plugged into a 120-volt line? If the freezer is used all the time, how much electrical energy does it use in a year?