Electricity - Mains Electricity Flashcards
how do fuses protect the user?
- stop the flow of current by melting if the current is too high.
- protect sensitive components and people because if the components function at too high a temperature it can cause a fire/shock
how do circuit breakers protect the user?
they break the circuit if the current is too high
how does insulation/double insulation protect the user?
prevents people from touching exposed wires and getting shocks
how does earthing protect the user?
provides a low resistance path to the earth so if someone comes into contact with a current instead of flowing through them and giving them a shock it flows through the earthing wire
what does current in a resistor result in?
the electrical transfer of energy and an increase in temperature
why are some components designed to have high resistance?
to make sure energy is transferred and heat is increased - for example, electrical heaters that have lots of resistors so a lot of heat is produced
what is the relationship between power, current and voltage?
power = current × voltage
what is the relationship between energy transferred, current, voltage and time?
energy transferred = current × voltage × time
what is alternating current?
AC is constantly changing magnitude and direction. AC is how mains electricity is produced.
what is direct current?
DC has a constant direction and is produced from a battery.
