Alternating Current Flashcards
An alternating current or voltage is one that what
Changes with time
What shows the waveform of an alternating current
An oscilloscope
The voltage goes up and down in a ……. Pattern
Regular
What is the trace we can see made by
An electron beam moving across a screen
What controls how fast the beam is moved across the screen
The time base
How can you set the time base
Using a dial on the front of the oscilloscope
What does the vertical height of the trace show
The input voltage at that point
Why does a direct current (d.c) show a straight line
Always the same voltage
What does an alternating current (a.c) source give
A regularly repeating waveform
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
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
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
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
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
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
