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Physics Section 3: Current Electricity > Alternating Current > Flashcards

Flashcards in Alternating Current Deck (15)
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0

What shows the waveform of an alternating current

An oscilloscope

1

An alternating current or voltage is one that what

Changes with time

2

The voltage goes up and down in a ....... Pattern

Regular

3

What is the trace we can see made by

An electron beam moving across a screen

4

What controls how fast the beam is moved across the screen

The time base

5

How can you set the time base

Using a dial on the front of the oscilloscope

6

What does the vertical height of the trace show

The input voltage at that point

7

Why does a direct current (d.c) show a straight line

Always the same voltage

8

What does an alternating current (a.c) source give

A regularly repeating waveform

9

How to measure peak voltage, time period and frequency

The highest peak
Distance between successive peaks
1/time period of the distance between successive peaks= frequency

10

To compare a d.c supply and a a.c supply properly what do you need to do

Get the average of the a.c supply

11

How do you get the average voltage and current for a a.c supply
(R.m.s)

Dividing the peak voltage/current by root 2

12

What if you want to work out the power for an a.c supply

Use the average voltage and current just worked out.
And times them together

13

What about working out the resistance of a a.c supply

Doesn't matter, as peak values give you the same answer
R=V/I

14

Describe how oscilloscope used to display the alternating waveform so two complete cycles are visible

Connect to y input
Adjust the time base
Each horizontal division 2ms/20across screen