Mains Electricity Flashcards
How does an electric current work?
Electric current is the movement of charge carriers.
What does AC current stand for?
Alternating Current.
What direction does an AC current flow?
An AC current is consistently changing direction.
What is the frequency of an AC current?
The frequency us 50 cycles per second or 50 Hz (hertz)
What is the direction of a DC current?
A DC current always keeps flowing in the same direction.
What does a DC current stand for?
Direct Current.
What is a Cathode Ray Oscilloscope (CRO)?
It is similar to a voltmeter.
What happens if an AC supply is plugged into an oscilloscope?
You get a ‘trace’ on the screen which shows how the voltage changes over time.
The trace goes up and down in a regular pattern.
Sometimes it’s positive, sometimes it’s negative.
What happens if you plugged a DC supply into an oscilloscope?
The trace you get is a straight line.
What does the vertical height of an AC trace show?
At any point it shows the input voltage at that particular point.
What can be found by measuring the height of an AC trace?
The potential difference of the AC supply.
How do you find the voltage of a DC trace?
You measure the distance from the straight line trace to the centre line.
What is the equation for frequency?
Frequency (Hz)= 1 divided by time period (s)
