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Flashcards in Mains Electricity Deck (15)
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1
Q

What is electric current?

A

The movement of charge carriers

2
Q

What is the voltage of the mains?

A

230 V

3
Q

What kind of supply is the mains? What does this mean?

A

AC (alternating current). It is constantly changing direction

4
Q

What is the frequency of mains supply?

A

50 cycles per second or 50 Hz

5
Q

What kind of supply is a battery? What does this mean?

A

DC (direct current) - the current keeps flowing in the same direction

6
Q

What can electrical supplies be shown on?

A

An oscilloscope screen

7
Q

What is a CRO?

A

A cathode ray oscilloscope is basically a voltmeter

8
Q

What happens when you plug an AC supply into an oscilloscope?

A

You get a ‘trace’ on the screen that shows how the voltage of the supply changes with time. The trace goes up and down in a regular pattern - sometimes +ve, sometimes -ve

9
Q

What happens when you plug an DC supply into an oscilloscope?

A

The trace you get is a straight line

10
Q

What does the vertical height of an AC trace show?

A

The input voltage at that point. By measuring the height of the race you can find the p.d of the AC supply

11
Q

What represents the voltage on a DC oscilloscope trace?

A

The distance from the straight line trace to the centre line (vertical)

12
Q

What does the gain dial control on an oscilloscope?

A

How many volts each centimetre division represents on the vertical axis

13
Q

What does the timebase dial control on an oscilloscope?

A

Controls how many milliseconds each division represents on the horizontal axis

14
Q

What is the equation for frequency?

A

Frequency (Hz) = 1/Time period (s)

15
Q

On an AC oscilloscope trace what represents the time period?

A

The distance between 2 peaks or 2 troughs. One whole u shape and one whole n shape