Electric Circuit

Components are connected together with electrical wire to form a closed loop.

Components are represented by symbols

Electric Circuit

•Electrical wire used to connect components is a conductor.•A conductor allows electric current to flow through it easily.•Good conductors include: copper, gold, silver, tin •Copper wire is generally used as it is most cost effective.

•All electrical wires have a plastic cover. •Plastic is an insulator.•An insulator does not allow current to flow through it.•Avoids electric shock.•Insulators include: plastic, glass, wood

Electric CircuitElectric Current is the flow of electrons around a circuit.

Electrons have a negative charge

Electric Circuit•Electric current is measured with an Ammeter•The ammeter is placed into the circuit (in series)•Unit of measurement is the Ampere or ‘amp’•Represented by the letter I .

I=3A

Electric Circuit•Voltage is measured using a Voltmeter.•The voltmeter is placed across a component (in parallel)•Unit of measurement is the Volt.•Represented by letter V.

Electric Circuit•Resistance is the opposition to the flow of electric current.•All components have resistance.•Electrical wire has resistance.•Unit of measurement is the Ohm (Ω)•Represented by the letter R

Ohm’s Law

Voltage , Current & Resistance are calculated using Ohm’s Law

IxRV

V

I RR

VI

I

VR

Series Circuit•Components are connected one after the other•There is only one path for current to flow around•The current at all points in a series circuit is equal

Series CircuitThe voltage is shared between the components in a series circuit.

•Components of equal resistance : voltage is shared equally

Series CircuitThe voltage is shared between the components in a series circuit.

•Components of unequal resistance : voltage is shared proportionally

Parallel Circuit•Components are connected side by side•There is more than one path for current to flow around

Parallel CircuitThe voltage across each path is always the same as the applied voltage

• When component resistance in each path is the same

Parallel CircuitThe voltage across each path is always the same as the applied voltage

• When component resistance in each path is different

Parallel CircuitThe voltage across each path is always the same as the applied voltage

• When there is more than one component in a path

Parallel Circuit•The current is divided between the paths proportionally (Ohm’s Law)