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Tektronix 2230 question

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chipwitch:
Total O-scope newb, here... I've been playing with my scope and an Arduino Mega board.  Thought it might be fun to try and generate a sine wave.  Also, it'd give me an idea how fast (or slow) Arduino AND my scope are.

Anyway, after building my circuit, I tried testing the output with a 10x probe.  I had to set the horizontal sweep to about 50ms.  I'm not getting a sine wave, but that could be an error in my code or circuit (the wave clearly resembles a square wave with a repeating anomaly like a couple pins are mixed up.)  My question is, how long should it take for the sweep to go from one side of the screen to the other?  It's close to half a second or so.

grumpydoc:
50ms is 50ms per division - 10 divisions across the screen = 50x10 = 500ms

chipwitch:
Hi Grumpydoc.  Yes, that makes perfect sense.  Sorry about that, I didn't think through the question before posting. 

What I should have asked is, is there any way to delay the phosphor from disappearing so fast?  A blip bouncing across the screen without a trail is difficult to read.  It doesn't look like a steady line until the sweep is set at about .1 ms.  Is this normal?

nixxon:

--- Quote from: chipwitch on April 02, 2013, 09:05:46 pm ---Hi Grumpydoc.  Yes, that makes perfect sense.  Sorry about that, I didn't think through the question before posting. 

What I should have asked is, is there any way to delay the phosphor from disappearing so fast?  A blip bouncing across the screen without a trail is difficult to read.  It doesn't look like a steady line until the sweep is set at about .1 ms.  Is this normal?

--- End quote ---

Check that the Scope is set to chop mode (not alternate mode) to make smoother looking traces at slow sweep speeds.

IIRC, 1 mS/div horizontal speed should look pretty smooth in chop mode.

Info found here: http://www.timcoengr.com/for_sale/Tektronix%202230.pdf

P31 green phosphor in the tek 2230 should persist for 10 uS to 1 mS according to http://www.jmargolin.com/xy/xymon.htm

** Persistence to 10% decay level:
       VS (Very Short) = less than 1 us
       S  (Short) = 1 us to 10 us
      MS (Medium-Short) = 10 us to 1 ms
      M (Medium) = 1 ms to 100 ms
      L  (Long) = 100ms to 1s

nixxon:
Here is a link to the 1985 Version of Tektronix' 
THE XYZs OF USING A SCOPE
With emphasis on the early (analog) 2200-series scopes:

http://njarc.org/books/XYZs%20of%20Using%20a%20Scope/XYZs_of_Using_a_Scope.pdf

And the rest of the interesting manuals are found here:

http://w140.com/tekwiki/wiki/2230

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