Electricity Flashcards
Static electricity
Is a build up of electric charge that can occur on good insulators e.g. Perspex rods
Polythene rod
Gains electrons
Perspex rod
Loses electrons
Unlike charges
Attract each other
Unlike charges
Repel each other
Earthing
Occurs when a charged object loses its charge to the Earth through a conductor
Current electricity
Symbol - I, Unit - Ampere, Unit symbol - A, Measured using - Ammeter
Potential difference electricity
Symbol - V, Unit - Voltage, Unit symbol - V, Measured using - Voltmeter
Resistance electricity
Symbol - R, Unit - Ohm, Unit symbol - Omega, Measured using - Ohmeter
Bulbs in series
If a bulb in series blows, none of them turn on. The same amount of current flows through each bulb in the series. The voltage is split up, depending on the size of the bulb
Bulbs in parallel
The lights in your house are connected in parallel. If bedroom light blows, the kitchen light is unaffected. The current is split between the bulbs, if they are the same size, then the current is split evenly. The same voltage flows through each bulb, so they are brighter than those in series.
Mains supply
The mains supply ( the electricity in our homes, supplied by the ESB ) is A.C
A fuse
Is a safety device that prevents the circuit from overheating, it will melt when it is too hot, breaking down the circuit
Circuit breaker
Is used in the fuse board of the home, and this trips, to stop the flow of current from entering the house
Why is a circuit breaker preferable
When a fuse blows it has to be replaced, modern houses have circuit breakers which act like a bimetallic strip and simply switch off if the current gets too big
