Electrical circuits
اسلاید 1: S.MORRIS 2006ELECTRICAL CIRCUITSMore free powerpoints at www.worldofteaching.com
اسلاید 2: The CELLThe cell stores chemical energy and transfers it to electrical energy when a circuit is connected.When two or more cells are connected together we call this a Battery.The cells chemical energy is used up pushing a current round a circuit.
اسلاید 3: What is an electric current?An electric current is a flow of microscopic particles called electrons flowing through wires and components. +-In which direction does the current flow? from the Negative terminal to the Positive terminal of a cell.
اسلاید 4: simple circuitsHere is a simple electric circuit. It has a cell, a lamp and a switch. To make the circuit, these components are connected together with metal connecting wires.celllampswitchwires
اسلاید 5: simple circuitsWhen the switch is closed, the lamp lights up. This is because there is a continuous path of metal for the electric current to flow around.If there were any breaks in the circuit, the current could not flow.
اسلاید 6: circuit diagramcellswitchlampwiresScientists usually draw electric circuits using symbols;
اسلاید 7: circuit diagramsIn circuit diagrams components are represented by the following symbols;cellbatteryswitchlampmotorammetervoltmeterbuzzerresistorvariable resistor
اسلاید 8: types of circuitThere are two types of electrical circuits;SERIES CIRCUITSPARALLEL CIRCUITS
اسلاید 9: The components are connected end-to-end, one after the other. They make a simple loop for the current to flow round.SERIES CIRCUITSIf one bulb ‘blows’ it breaks the whole circuit and all the bulbs go out.
اسلاید 10: PARALLEL CIRCUITSThe current has a choice of routes.The components are connected side by side. If one bulb ‘blows’ there is still be a complete circuit to the other bulb so it stays alight.
اسلاید 11: measuring currentElectric current is measured in amps (A) using an ammeter connected in series in the circuit.A
اسلاید 12: measuring currentAAThis is how we draw an ammeter in a circuit.SERIES CIRCUITPARALLEL CIRCUIT
اسلاید 13: measuring currentSERIES CIRCUITPARALLEL CIRCUIT current is the same at all points in the circuit.2A2A2A current is shared between the components2A2A1A1A
اسلاید 14: copy the following circuits and fill in the missing ammeter readings.??4A4A4A3A??1A?3A1A1A
اسلاید 15: measuring voltageThe ‘electrical push’ which the cell gives to the current is called the voltage. It is measured in volts (V) on a voltmeterV
اسلاید 16: Different cells produce different voltages. The bigger the voltage supplied by the cell, the bigger the current.measuring voltageUnlike an ammeter a voltmeter is connected across the componentsScientist usually use the term Potential Difference (pd) when they talk about voltage.
اسلاید 17: measuring voltageVThis is how we draw a voltmeter in a circuit.SERIES CIRCUITPARALLEL CIRCUITV
اسلاید 18: Vmeasuring voltageVVV
اسلاید 19: series circuit1.5V voltage is shared between the components1.5V3V
اسلاید 20: voltage is the same in all parts of the circuit.3Vparallel circuit3V3V
اسلاید 21: measuring current & voltagecopy the following circuits on the next two slides.complete the missing current and voltage readings.remember the rules for current and voltage in series and parallel circuits.
اسلاید 22: measuring current & voltageVV6V4AAAa)
اسلاید 23: measuring current & voltageVV6V4AAAAb)
اسلاید 24: answers3V3V6V4A4A6V6V6V4A4A2A2A4Aa)b)
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