Oscilloscope Newbie

Discussion in 'General Electronics Chat' started by Lissajous, May 17, 2006.

  1. Lissajous

    Thread Starter New Member

    May 17, 2006
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    hi I'm Lisa, I'm new here and trying to learn the oscilloscope as a measuring tool.

    i would like to know how to measure using oscilloscope say 5V on a test point in a circuit. will i be able to see the Voltage (amplitude) in Channel 1 directly by hooking the probe tip and its ground? Or do I need the trigger control settings? I can read 5V using a Digital voltmeter but I can't see this 5V on the oscilloscope.

    A detailed instruction will be of great help.

    Thanks for your help guys.....
     
  2. Gadget

    Distinguished Member

    Jan 10, 2006
    613
    0
    Make sure channel1 is set to DC mode. Set your ampltude to 1 volt per division (or 0.1 v per div if using a divide by 10 probe)
    Press the grounding switch, or short the probe and earth clip together and adjust the position of the 0 volt reference line to a grid line nearer the bottom of the screen.
    Now make sure the grounding switch is off, connect the earth clip of the probe to the earth or 0 volts of the circuit, and use the probe tip to measure the voltage. The trace should jump up 5 divisions for 5 volts.
    The trigger control is for more complex waveforms then pure DC... although selecting an appropriate timebase, trigger etc may allow you to see ripple that might be present on the DC.
     
  3. Papabravo

    Expert

    Feb 24, 2006
    10,173
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    Trigger Settings of "Auto", "Normal" and "Ext" are typical. Use "Auto" to see unchanging signals. Use "Norman" and either postive edge or negative edge to see signals which are changing.
     
  4. Lissajous

    Thread Starter New Member

    May 17, 2006
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    last question for this thread ; )

    how about pulse width and rise time measurements when using an oscilloscope?

    kindly go into details. thanks again!
     
  5. Guy

    New Member

    May 25, 2006
    1
    0
    As you probably know, an oscilloscope is a device for measuring signals graphically--i.e., in a time-versus-voltage format. As such, the scope can be used to measure a simple DC signal (a constant voltage over time), or it can be used to measure a changing or pulsed signal. This is the type of signal you are asking about. To measure a pulse--single or repeated--on the oscilloscope, simply set the horizontal control (Time/Div Control) to the proper time setting. For example, if you are measuring a positive pulse that has a width of 500us (1khz), you would set the horizontal control to a setting that would allow you to view the signal on the scope's screen. It is important to keep in mind that the horizontal scale of the screen is divided into 10 equal divisions ( a heavy vertical line typically divides the screen in the middle). In the above example, a horizontal setting of 250us or 500us--meaning that each horizontal division on the scope is equal to 250us or 500us--would be suitable. If the pulse is not visible on the screen or appears to be "scrolling," check the trigger setting on the scope; it should be set to Auto. This will keep the signal stable for measurement. Finally, remember that you will also need to verify that the vertical deflection (Volts/Div) is set correctly (to view the amplitude of the pulse), and, last but not least, that the Channel input coupling is set to either AC or DC (not ground). I hope this helps.
     
  6. Lissajous

    Thread Starter New Member

    May 17, 2006
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    thank you!
     
  7. radiosmoke

    Member

    May 30, 2006
    17
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    Funny that you go by the name of Lissajous.
    By the way what does the word Lissajous mean?
    In your own words that is, I'm just curious.

    Do you have a manual on how to use an Oscope?
    If not go to the web page for Tektronics and browse for the free download "The ABC's of Scope's"

    It wasn't mentioned but if you are measuring DC. the trace will be flat. Its Just as was said it will be on something other then the bottom grid. If you don't see it at first the voltage may be to small and you would have to lower the setting for v/div and adjust the cursor. I would start by moving the cursor to the center of the CRT, then watching while your probing the voltage point. You can then determine if the voltage is + or -. If its - then move your cursor to the top grid and read the divisions down to where the line appears. Just the opposite for a + voltage.
     
  8. n9352527

    AAC Fanatic!

    Oct 14, 2005
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  9. Papabravo

    Expert

    Feb 24, 2006
    10,173
    1,797
    Lissajous curves are generated from parametic equations where x an y are sinusoidal functions of the parametric variable. They were studied in detail by Jules-Antoine Lissajous,and others, from about 1815 to 1857.
     
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