Strange oscilloscope functions

John Bond

Hi Guys
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I’ve had a Parallax Optascope for a while.
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When I first used it, I noticed that the 500mv function gave the same reading as the 1V (1 volt per graduation). I use it manly for fault finding so this wasn’t a problem.
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Last Sunday, I was monitoring a wave form and I noticed the display of the waveform didn’t increase above 10V, regardless of what voltage the actual waveform was. I don't think I've ever measures a signal larger than 10V before...
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Are these problems:
········ A hardware bug?
········ Something in the Windows software?
········ A fault with the device?

Kind regards on this glorious hot humid·day in Kwa Dukuza - South Africa.

John Bond

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John R.

Based on memory from other threads, I believe that the Parallax o'scope caps out at 10 Volts. I also believe that there is a voltage, not much above 10, that will damage the 'scope.

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John R.

8 + 8 = 10

Chris Savage

John R. is correct…The input voltage range is -10V to +10V (20 V range peak to peak). If you go much above or below that you could damage the scope. I have never tried the 500mV/1V before, however we do have updated software coming very soon. Take care.

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Chris Savage
Parallax Tech Support

Beau Schwabe

If you need to go above +10V or below -10V, you can follow this link on what's needed for a X2 probe... Just remember that the readings you "see" on the scope will be 1/2 of what they actually are.

http://forums.parallax.com/showthread.php?p=617175

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Beau Schwabe

IC Layout Engineer
Parallax, Inc.

John Bond

Sorry Guys

I had the figure 20 Volts stuck in my brain, not 20v peak to peak... Well, I took it to 32 volts for a short period and it still works fine!!

Regards from Africa on this hot sunny Saturday.

John Bond

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