2. Direct current Electricity

3. Do Now What is Direct Current Electricity ? List the components of a simple circuit List few examples for insulators List few examples for conductors

4. L.I: learning about Direct Current Electricity S.C: I am able to define current electricity I am able to identify components of electric circuit. I am able to draw simple circuit diagram. I am able to differentiate series and parallel circuit I am able to describe the use of conductors and insulators

5. Definition: The electrical current is a flow of charged particles Electricity is a form of energy that can be easily changed to other forms. What is Electricity ???

6. Types of current Two Types of Current: DC—Direct Current—produced by solar cells and chemical cells (batteries) Current only flows in one direction.

7. 2 nd type of current AC—Alternating Current Current flows back and forth (alternates) Found in homes Generators produce AC current

8. Electric Charges Electric charges are made up of positive charges (protons) and negative charges (electrons). When these charges flow in a circuit, a current is produced.

9. How does direct electricity flow? The battery in a circuit gives energy to the electrons and pushes them around a circuit, from the negative terminal of the cell, round the circuit and back to the positive terminal of the cell.

10. Electric Circuits Electric circuits are made up of electrical components Electric circuits are made up of electrical components These components must be joined together without any gap in between to form a closed circuit. These components must be joined together without any gap in between to form a closed circuit. connecting wires electric cell circuit boardlight bulb Note: Components refer to the light bulb, wires, battery

11. Electric Circuits Incomplete circuits are called open circuits. Incomplete circuits are called open circuits. connecting wire is missing no source of electrical energy Both the circuits in the diagram are incomplete, hence they are known as “open circuits”.

12. An electric current flows only when there is: A source of electrical energy – battery, power supply A source of electrical energy – battery, power supply A component to convert energy into another form – light, motor or heater A component to convert energy into another form – light, motor or heater a complete circuit without any breaks a complete circuit without any breaks connecting wires electric cell circuit boardlight bulb

13. Examples of circuit diagrams:

14. circuit diagrams In circuit diagrams components are represented by the following symbols; cellbatteryswitchlamp motorammetervoltmeter buzzer resistor variable resistor

15. Series Circuit All parts of the circuit are connected one after another in a loop There is only one path for the electrons to follow If one part goes out The circuit goes from closed to open Electricity will not flow All parts go out The voltage is split through each part of the circuit The current is the same throughout the circuit Example: Christmas Tree Lights

16. Series Circuit Examples A complete circuit turns the light bulbs on

17. Series Circuit Examples The burnt bulb stops the electron flow to the rest of the circuit This Light Bulb is Burnt Out

18. Parallel Circuit There is more than one path or branch for the electrons If a break occurs in one branch, the electrons can still flow in the other The voltage is the same throughout each branch The current is split through each branch Example: Household Wiring

19. Parallel Circuit Examples Current divides and has more than one path A B PATH #1 PATH #2

20. Parallel Circuit Examples Even though Bulb “B” is burnt out, the current still goes through the other circuit and Bulb “A” remains lit This Light Bulb is Burnt Out B A

21. Circuit Diagrams ComponentSymbolComponentSymbol An electric cellBattery Light bulb (lamp)Switch Switch (open) Switch (closed) Connecting wires (not joined) Connecting wires (joined) ++ Symbols are used to represent the various electrical components in circuits.

22. Conductors A conductor is a material that current can pass through easily A substance such as steel, has free electrons and allow current to occur

23. Insulators A material in which electrons are not able to move easily is an insulator. These does not have free electrons and does not allow current to occur Most plastics are insulators

24. Examples Metal Paper clips Silverware Wires Water

25. Tea cosy, burger box and thermos flask all prevent the transfer of heat. Look at these things. These are insulators too. What do they do?