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Simple circuits

Electricity. Simple circuits. I will challenge myself to identify the symbols used in electrical circuits and draw simple circuits. I will aspire to be able to explain why it is important that a circuit is complete in order to work. Electricity. Electric current

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Simple circuits

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  1. Electricity Simple circuits

  2. I will challenge myself to identify the symbols used in electrical circuits and draw simple circuits. I will aspire to be able to explain why it is important that a circuit is complete in order to work. Electricity Electric current When electric charges move in a wire, we say an electric current flows in the wire. For a current to flow, we need two things: • Something to make electricity to flow • A complete path for the current to flow. This is called an electric current.

  3. I will challenge myself to identify the symbols used in electrical circuits and draw simple circuits. I will aspire to be able to explain why it is important that a circuit is complete in order to work. Drawing electric circuits We draw circuit diagrams and symbols to draw circuits that could be quite complicated! Wires are drawn as straight lines and the components always have the same symbol.

  4. I will challenge myself to identify the symbols used in electrical circuits and draw simple circuits. I will aspire to be able to explain why it is important that a circuit is complete in order to work. A battery always needs to be a small line, big line, small line followed by a big line – can not have two big lines next to each other or two small lines next to each other

  5. Match the circuit to the diagram A D ❶ ❸ B 1B ❷ ❹ 2D 3C C 4A

  6. I will challenge myself to identify the symbols used in electrical circuits and draw simple circuits. I will aspire to be able to explain why it is important that a circuit is complete in order to work. Draw these circuits 2) 1) A circuit with: 1 cell 2 light bulbs 1 ammeter

  7. I will challenge myself to identify the symbols used in electrical circuits and draw simple circuits. I will aspire to be able to explain why it is important that a circuit is complete in order to work. Answers – you could have any of these 1) 2)

  8. Electrical energy Electricity is a way of transferring of energy We need that energy for different reasons – boiling our kettle, light bulbs

  9. Electrical energy Current – is a flow of electrical charges called electrons around the circuit The cell or battery is what pushes the electrons around the circuit and transfers the energy to them

  10. Electrical energy Which direction does it flow? It moves from the negative part of the cell to the positive part

  11. Measuring current Units for current: Measured using an: Amps (short for amperes) ammeter

  12. What are the missing words? electrons Current is a flow of ___________ around a circuit. Current is measured in __________ using an _________ placed in a circuit. The current moves from the ________ to the _________ side of the cell. amps ammeter negative positive

  13. Series circuit In a series circuit, every part of the circuit is on the same path. The current can only go one way.

  14. What do you notice about the readings on the ammeter? A2 = 3A A1 = 3A The current is not used up, it will be the same as in the battery/cell!

  15. Current in a series circuit If the current here is 2 amps… The current here will be… 2 A The current here will be… 2 A And the current here will be… the In other words, the current in a series circuit is ____ _______ at any point. 2 A same

  16. A B Parallel circuits The current can choose which path to travel around the circuit. It can split at point A or join again at point B.

  17. A1 = A2 A3 + A4 + A5 = A2 A1 is equal to A2 as they are in series and current is the same at all points in a series circuit. A3 + A4 + A5 = A2 as in a parallel circuit, the current adds up to the current that is flowing through the battery or cell.

  18. Pick the correct statement Current is measured in volts Current is measured in amps Current is measured in joules Current is measured in ohms

  19. Pick the correct statement Current flows from the positive to the negative part of the cell Current is a flow of electrons Current is the flow of protons from the positive part of the cell to the negative part of the cell Current is the flow of electrons from the positive part of the cell to the negative part

  20. Pick the correct statement Current is the same at different points in the circuit Current is used up in the circuit Current is split equally between the different components Current is a unit of measure

  21. Potential difference Potential difference is sometimes called voltage. In a circuit, the provides the driving force to push the charge around the circuit. battery Potential difference

  22. Measuring potential difference You would use a voltmeter to measure potential difference. The units are volts.

  23. Measuring potential difference You measure the potential difference across something in the circuit, such as a bulb.

  24. In a series circuit: The potential differences across the components add up to the potential difference of the battery or cell. What do you notice about the voltage seen on the voltmeters? V1 = 2 V V2 = 3V V3 = 4V Battery = 9V

  25. Voltage in a series circuit In a series circuit, the voltage across the components adds up to the voltage of the battery or cell so each bulb would be 2 V. If the voltage across the battery is 6V… …what will the voltage across two bulbs be? 4 V

  26. Voltage in a series circuit In a series circuit, the more bulbs added, the dimmer they become as the voltage from the battery or cell is spread out over the bulbs. The more batteries there are, the brighter the bulbs will become.

  27. In a circuit, the greater the potential difference across a bulb, the brighter the bulb will be. Write whether the bulbs in the circuits below will be brighter, dimmer, or the same as in a circuit with just one bulb and one cell. The same Dimmer Brighter

  28. In a parallel circuit: The potential differences across the components areequalto the potential difference of the battery or cell.

  29. Voltage in a parallel circuit In a parallel circuit, the voltage across the components is equal to the voltage of the battery or cell If the voltage across the batteries is 4V… What is the voltage here? 4 V And here? 4 V

  30. In a parallel circuit, if one bulb goes out, all the other bulbs will stay on. In a series circuit, if one bulb goes out, they all will go out.

  31. Electrical circuits Do you think the below statements are true or false? True Electrical current is the flow of charge around a circuit. Current can still flow when the circuit is broken. The total current in a circuit is always the same. The moving charges in a circuit are electrons. The charges in a circuit flow from positive to negative. False True True False

  32. Resistance In a circuit, all wires and components resist current. Resistance is a measure of how hard it is for electrons to move in an electrical circuit

  33. Calculating resistance Voltage is measured in volts (V) ÷ Current is measured in amps(A) X Resistance is measured in ohms (Ω)

  34. Calculating resistance Use the formula on the previous slide (which you learnt with Miss Johnson) complete the table.

  35. Answers

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