Electricity Parallel and Series Circuit (HBL 2)

• Electric Circuits• What makes a Bulb brighter?

Electric Circuits

• Closed Circuit

Electric current flows through it.

• Open Circuit

There is a break.

Electric current does not flow through it.

Electric Circuits

• Circuit diagrams record the components and connections of a circuit in a simple and clear way.

• Basic Circuit symbols:

battery

2 batteries

wireswitch

bulb

Components of an Electric Circuit

• Actual circuit versus Circuit diagrambattery

wire

battery holder

switchbulb

battery

wire

switch bulb

In a circuit, the brightness of a bulb depends on:

a) The number of batteries used(the greater the number of batteries, the brighter the bulb).

b) Arrangement of components of the circuit.

Factors that affect the brightness of a bulb:

1. The number of batteries (in series)

Single battery Multiple batteries

dimmer brighter

More ……

• As more batteries are added in series, more current is available and the bulbs become brighter.

• When too many batteries are added, the current is so great that one of the bulbs may blow/fuse (too much heat is made by the filament that it burns out).

Factors that affect the brightness of a bulb:

2. The arrangement of batteries

Batteries arranged in parallel

Batteries arranged in series

dimmer brighter

More ……• Batteries need to be connected with the poles

in the proper direction for current to flow – positive end of one battery needs to be joined to the negative end of another.

• When the number of components is the same, the bulb of the circuit with batteries arranged in series is brighter than that in parallel.

• However, if one battery is removed, only the bulb of the circuit with batteries arranged in parallel remains lighted up.

Factors that affect the brightness of a bulb:

3. The number of bulbs

Single bulb Multiple bulbs

brighterdimmer

More ……

• The greater the number of bulbs, the dimmer they are.

Bulbs arranged in Parallel

Bulbs arranged in Series

Factors that affect the brightness of a bulb:

4. The arrangement of bulbs

brighter dimmer

Bulbs in series vs Bulbs in parallel

Points for comparison

Arrangement of bulbs in:

Series Parallel

Number of paths for the electric current

Only one path; current passes through

components one after another

2 or more paths; current splits up and

passes through each branchat the same time;

paths are independent of each other

Brightness of bulbs

Dimmer Brighter

If one bulb is removed or damaged

Electric current cannot flow through the circuit, the

remaining bulb will not light up

Electric current can still flow through the other path and the

other bulb still lights up

Application - Used in the connection of circuits in the houses; twinkling lights, bumper cars in fun fairs

Application ……• All the lights in our houses were

connected in series, then we have to turn on all the lights at the same time. If one bulb blows, then all the bulbs will not light up. Hence household lighting and wiring is arranged in parallel. Each bulb has an individual switch to control it.

• Christmas Tree lightings

The End