Mains Electricity Flashcards
What is the approximate voltage of the UK mains electricity supply?
230v
What type of current is mains?
Alternating
What is alternating current?
Current that is constantly changing direction
What is the frequency of the AC mains supply?
50Hz
What type of current do cells and batteries supply?
Direct current
What is direct current?
Current that always flows in the same direction
What is a CRO?
Similar to a voltmeter
If you plug an AC supply into an oscilloscope you get a trace showing how voltage changes with time (sometimes positive, sometimes negative)
What happens if you plug a DC into an oscilloscope?
You get a straight line
What does the vertical height of an AC trace show?
Input voltage at that point
By measuring the height of the trace what can you find?
The potential difference of the AC supply
For DC what is the voltage?
The distance from the straight line trace to the centre
What does the Gain dial control?
How many bolts each centimetre division represents on the vertical axis
What does the timebase dial control?
How many milliseconds each divisons represents on the horizontal axis
How do you work out frequency?
1/ time period
