Series and parallel circuits

What is a series circuit?

A circuit with a single loop of wire.

What is a parallel circuit?

A circuit with two or more loops (branches) of wire.

What are the characteristics of series circuits?

• There is the same current through each component

• The total potential difference of the power supply is shared between the components

• The total resistance of two components is the sum of the resistance of each component.

What are the characteristics of parallel circuits?

• The potential difference across each component is the same

• The total current through the whole circuit is the sum of the currents through the separate components

• The total resistance of two resistors is less than the resistance of the smallest individual resistor

What are the two types of current?

Direct and alternating

What type of current is current from a cell?

Direct current

What is the key feature in alternating current?

The current is always changing direction.

What type of current is the mains supply in the UK?

Alternating. (50 Hz and 240V)

What is meant by direct potential difference?

One that is either positive or negative - charge is always flowing in the same direction.

What is meant by alternating potential difference?

One that flunctuates between negative and positive.

How are most electrical appliances are connected to the mains?

Using three-core cable.

What colour is the live wire?

Brown.

What does the live wire do?

The live wire carries the alternating potential difference from the supply.

What color is the neutral wire?

Blue.

What does the neutral wire do?

The neutral wire completes the circuit.

What colour is the earth wire?

Green and yellow stripes.

What does the earth wire do?

The earth wire is a safety wire to stop the appliance becoming live.

What are everyday electrical appliances are designed to bring about?

Energy transfers

What does the amount of energy an appliance transfers depend on?

How long the appliance is switched on for and the power of the appliance.

What happens when charge flows in a circuit?

Work is done.

What is the national grid?

A system of cables and transformers linking power stations to consumers.

How is electrical power transferred from power stations to consumers?

Through the national grid.

What are Step-up transformers are used for?

To increase the potential difference from the power station to the transmission cables then step-down transformers are used to decrease, to a much lower value, the potential difference for domestic use.