The CRO from GO to WUAO
- An oscilloscope is used as often as possible due
to the fact that it can provide much more information
regarding the signal that is being measured than most
other measuring devices that are currently being used
within the lab.
- The major advantage of the oscilloscope over
other measuring devices used in the lab such as the DMM is the
fact that we can measure the amplitude of the signal, the
frequency of a signal and we can also see if the signal
is of the shape that we are expecting.
- So essentially the oscilloscope can be used to
make quantitative and
- For example if we are looking at an incoming sine
wave, from the CRO one can assess the signal amplitude,
frequency and quality.
- Some may argue that the best solution to the
problem of measuring a D.C. signal would be to use a DMM, this is
true in most cases, but if the purity of the D.C signal
is an important factor a CRO would also be useful to
check for any A.C ripple in the signal.
- In general the biggest use for the Oscilloscope
in first year is for the accurate measurement of A.C.
If we consider the measurement of A.C. signals. In
particular a 10V peak to peak sine wave with a frequency of 1kHz.
- The amplitude of the signal is 10 volts peak to
peak. Now if we measure this signal on a DMM the
display would look as follows:
- If you are wondering why the display reads 7.07 Volts
it is because the DMM
takes A.C. readings as the Root Mean Square value of the
voltage rather than the Peak to Peak Voltage. And it also
tells us nothing about the frequency or quality of the
- In comparison if we measure the signal using a
CRO the display
would look much like the image below:
- This perspective shows us the peak to peak
amplitude of the signal (calculated using the vertical
divisions on the CRO display
) and also shows us the frequency of
the signal (calculated using the horizontal divisions on
the CRO display).
- Finally the fact that the signal is actually a
good quality sine wave can be verified (i.e. is it the
correct shape?) in the obvious manner.
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Revised: 15 September 2004