O-scope square waveform basics?

[Lance Morgan]

I recently picked up a used two chan 20MHz 1020 Leader scope, very
similar to

www.tequipment.net/LeaderLS8022.html

I'm using (cheap?) Avex 10:1 passive probes

With probe tip at front ref signal 0.5V @ 1kHz (I think I properly
compensated the probe for LF), or trying to scope my car's Hall-Effect
sensor, I am getting the expected square wave, but sans any vertical
traces, like

_-_-_-_-_-_-_-_-


or like the lower pattern on 8022 pic above.

I'm a scope newbie, so I first and foremost expect pilot error, and/or
I don't know what a square waveform should look like...

When I just place my finger on the probe tip, at some settings I can
get either a sine wave, or something roughly like an (inverted)
catenary curve

Or is something possibly wrong w/the scope not registering seeing
square pulses? or w/the CRT's deflection on one axis?

Thank you,
Lance

 

[Lance Morgan]

CJT wrote:

Lance Morgan wrote:


With probe tip at front ref signal 0.5V @ 1kHz (I think I properly
compensated the probe for LF), or trying to scope my car's
Hall-Effect
sensor, I am getting the expected square wave, but sans any vertical
traces, like

_-_-_-_-_-_-_-_-


or like the lower pattern on 8022 pic above.


Thank you,
Lance

It sounds like it's working fine. What you're calling the vertical
portion of the trace happens much faster in time than the horizontal.
Thus, it's not nearly as bright. If you cranked the brightness up
you could perhaps see it, but there's no need -- you know it's there.

You could also speed up the timebase and try to see more of the
risetime of the square wave.

Thanks. I'm carefully fiddling w/the settings, including CRT, but it
makes it difficult to see if square wf is really square - hard to ck for
rounded corners/distortion. I was hoping to see a nearly frozen/slow
"showcase" pattern

I'll try to make better use of the graticule and keep acclimatizing

 

[CJT]

Lance Morgan wrote:

I recently picked up a used two chan 20MHz 1020 Leader scope, very
similar to

www.tequipment.net/LeaderLS8022.html

I'm using (cheap?) Avex 10:1 passive probes

With probe tip at front ref signal 0.5V @ 1kHz (I think I properly
compensated the probe for LF), or trying to scope my car's Hall-Effect
sensor, I am getting the expected square wave, but sans any vertical
traces, like

_-_-_-_-_-_-_-_-


or like the lower pattern on 8022 pic above.

I'm a scope newbie, so I first and foremost expect pilot error, and/or
I don't know what a square waveform should look like...

When I just place my finger on the probe tip, at some settings I can
get either a sine wave, or something roughly like an (inverted)
catenary curve

Or is something possibly wrong w/the scope not registering seeing
square pulses? or w/the CRT's deflection on one axis?

Thank you,
Lance

It sounds like it's working fine. What you're calling the vertical
portion of the trace happens much faster in time than the horizontal.
Thus, it's not nearly as bright. If you cranked the brightness up
you could perhaps see it, but there's no need -- you know it's there.

You could also speed up the timebase and try to see more of the
risetime of the square wave.