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Usage of Oscilloscope 1
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Usage of Oscilloscope
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Oscilloscope An oscilloscope is a type of electronic test equipment
that allows observation of constantly varying signal voltage
It stores it with 8 bits of precision Then makes a graph of voltage
versus time
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OBJECTIVES
In this module we will see how use an oscilloscope to . . .
Measure direct current (D.C.) voltage and
Measure alternating current (A.C.) voltage
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Oscilloscope Screen The screen has ruled
divisions both horizontally and vertically
The major divisions are marked off in centimeters, the middle lines also have minor divisions every 0.2 of a centimeter
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Input Channel Selector• This area is broken into two parts: the left half for
channel A and the right half for channel B
• In the center of this section lies the mode switch that determines which channel will serve as an input to the scope: A, B or Dual.
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Control Panel The section to the
right of the screen contains the controls necessary to adjust the triggering and sweep time of the waveform
This section is generally used when measuring the period of A.C. waveforms
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Mode Switch
The oscilloscope is capable of measuring voltages from two different sources
The mode switch is used to alternate between sources
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Function Buttons These button are
located at the upper right corner of the generator. Selecting a button sets the type of voltage change over time as a square, triangular or sine wave
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Connecting the Function Generator to the Oscilloscope
• Connect the alligator clip of the black lead from the function generator to the alligator clip of the black lead from the oscilloscope
• Do the same with the red leads
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Position the wave so that the bottom of a wave is lined up with one of the cm markings
Measure the number of cm’s from the bottom of the wave to the top
Multiply the number of cm’s by the volts/cm sensitivity to get the maximum peak voltage
Measuring Voltage
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Changing the Oscilloscope Settings• Watch the wave form change
as you change the volts/cm dial to 10 and the sweep time/cm dial to 5 ms/cm
• Adjust the triggering level knob if necessary to get a stable image
• We should still be reading 20-25 V and 100 cycles/sec
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Using the 5X Feature on Horizontal Knob
Pull the horizontal knob OUT
Notice that it spreads out wave magnifying it 5 times. We can use this feature to zero in on part of the wave
Push it back in before continuing
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Make sure the picture is centered on the screen using the vertical and horizontal position dials
Flip the source switch to internal If necessary, adjust the triggering level knob until you
get a steady picture Adjust the intensity and focus to get a good sharp
image
Summary Measuring AC Voltage
