Electricity

PeopleBenjamin FranklinProved that lightning was electricity by flying a kite in a lightning stormHelped people understand the principles of electricity

Thomas EdisonInvented the electrical light bulb

What is electricity?Electricity is a form of energyIt is caused by a flow of tiny particles called electrons through a material

ElectricityElectricity is a flow of electric charges along a wire.

ElectricityElectricity is a flow of electric charges along a wire.This flow of electric charge is called a current.

Current is measured in the units of Amps (A).

What is an Electrical Circuit?A circuit is an electrical device that provides a path for electricity to flow

Complete or Incomplete?

A complete circuit is where all the components of a circuit are joined up and there are no gapsThe pathway for electricity is complete

An incomplete circuit is where the pathway for electricity is brokenThe electricity cannot flow

Circuit Diagramscellswitchlampwires

Circuit DiagramsRULES:Each component has its own symbolWires connect the componentsWires must be drawn with straight lines with a rulerThe wires should never cross each other

Component Symbols a cellThe cell stores chemical energy and transfers it to electrical energy when a circuit is connected.

The long line is the positive end

The short line is the negative end

BatteryWhen 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.

It is important that each cell faces the right way

SwitchA switch can be open (as shown) or closedWhen the switch is open, the circuit is incomplete no electricity can flowWhat happens when the switch is closed?

Bulb / LampThe lamp lights up when electricity flows through it

What would happen to a lamp if there was an open switch in the circuit?

WiresThe wires which carry electricity consist of two parts: The metal wires (conductor). The plastic coating around the metal wires (insulator).

Prevents people from being electrocuted.wires

VoltmeterThe voltmeter measures the voltage of the circuit

We will discuss this in another lessonAmmeterThe ammeter measures the current in the circuit

We will discuss this in another lesson

ResistorA resistor can change the amount of current in a circuitIn a variable resistor, the resistance can be changed.

Resistance

FuseA fuse is a safety deviceWhen the current is too high, the fuse breaks

Example

The wire inside a 3A fuse will melt when the current is greater than 3A.MotorA motor can be fitted into a circuit

What do you think happens to a motor in a complete circuit?

Circuit SymbolsVoltmeterAmmeterVariable ResistorSwitchBulbMotorCellBattery

types of circuitThere are two types of electrical circuits;SERIES CIRCUITSPARALLEL CIRCUITS

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.

PARALLEL CIRCUITSThe current has a choice of routes (paths).The components are connected side by side. If one bulb blows there would still be a complete circuit to the other bulb so it stays lit.

measuring currentElectric current is measured in amps (A) using an ammeter connected in series in the circuit.AVThe electrical push which the cell gives to the current is called the voltage. It is measured in volts (V) on a voltmeter

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