Household Electricity Flashcards
How do you calculate the frequency on an oscilloscope trace?
1 / time period
How do you find the time period on an oscilloscope trace?
Measure the time of one complete cycle
What is direct current?
Current that always passes in the same direction
What type of current do cells and batteries use?
Direct current
What type of current does main electricity use?
Alternating current
What is alternating current?
One that constantly changes direction
In the UK, what’s the frequency of mains electricity?
50Hz
In the UK, what’s the potential difference of mains electricity?
About 230V
How are most appliances connected to mains?
Using a cable and a three pin plug
Why do some appliances only need a two core cable?
As they are double insulated
What’s the difference between a two and three core cable?
A two core doesn’t have an earth wire
Name the 6 key components in a three pin plug
Live wire, earth wire, neutral wire, fuse, cable grip, outer insulation (on the cable)
What are the metal parts of a plug made of? Why?
Copper or brass, as they are good conductors
What is the case, cable and cable insulation in a plug made from? Why?
Rubber or plastic, they are insulators and are flexible
If an electrical fault causes too great a current, the circuit is disconnected by either…
A fuse, or a circuit breaker in the live wire
