On Fri, 15 Feb 2019 14:56:25 -0800, Jeff Liebermann
wrote:

On Fri, 15 Feb 2019 11:07:18 -0800, wrote:

On Thu, 14 Feb 2019 13:09:32 -0800, Jeff Liebermann
wrote:

On Thu, 14 Feb 2019 11:25:53 -0800, wrote:


So, as near as I can tell, the probes are all right, at least they
all act the same. But what causes the distorted square wave at the 1x
setting?

It's caused by the lack of high frequency response (i.e. rise time) in
X1 mode. For a typical X10/X1 switchable problem, the frequency
response is MUCH higher in X10 than in X1. For example:
https://www.tiepie.com/en/usb-oscilloscope/accessories/oscilloscope-probe-250mhz-x1-x10
Notice that the bandwidth is 250MHz in X10 but only 6MHz in X1.
This one is closer to what I think you bought:
https://www.tiepie.com/en/usb-oscilloscope/accessories/oscilloscope-probe-60mhz-x1-x10
60MHz bandwidth in X10 and 6MHz bandwidth in X1.

The frequency I was using was 1KHz. That's what the 'scope puts out
and what the function generator was set at. With a 100MHz probe
shouldn't a 1 KHz signal be low enough to avoid the rise time issue?

No. The rise time and bandwidth are not related to the frequency of
the input waveform. Basically:
Bandwidth * RiseTime = 0.35
https://www.tek.com/support/faqs/how-bandwidth-related-rise-time-oscilloscopes
If the rise time of the 1KHz waveform is very small, you will need a
probe and scope with a high bandwidth in order to see it. If these
are lacking, the scope will display a much slower rise time than what
the 1KHz generator is actually producing.

For the two scope probes I mentioned above, both probes have 6MHz
bandwidth.
RiseTime = 0.35 / Bandwidth = 0.35 / 6*10^6 = 0.058 * 10^-6
= 58 * 10^-9 = 58 nsec rise time
with an X1 probe.

You can also mangle the waveform by setting the vertical amplifier set
to AC instead of DC. That will cause the top and bottom of the square
wave to sag like a capacitor charge/discharge curve.

I can't tell which of these is the problem because your description of
the waveform as "really weird results" and "slightly distorted" isn't
really sufficient.

I didn't even know about the difference in the frequency response.

Now, you know. There should be something on the web that covers all
this. Search for:
https://www.google.com/search?q=analog+oscilloscope+basics

EEVblog #453 - Mysteries of x1 Oscilloscope Probes Revealed
https://www.youtube.com/watch?v=OiAmER1OJh4 (29:48)

ABCs of Probes
https://download.tek.com/document/02_ABCs%20of%20Probes%20Primer.pdf
See Pg 8, 35-37.

Is
this one of the reasons that people recommend using the 10X setting
unless the 1x setting is needed?

Yep.

That the only time the 1X setting is
used is when the signal needs to be measured un-attenuated?

Nope. There are plenty of uses for an X1 probe. If the signal is
very low amplitude, it's easier to see using either a direct
connection to the scope input or an X1 problem. If the frequency is
low enough that you don't care about bandwidth, then X1 is just fine.
Thanks Jeff,
Below is an answer I gave to Mike about the wave shape and other
features. The description should give you a better idea of what I am
seeing. At least I hope it does.

"Whoops! It looks like the wave is over compensated. So it looks
like
at the beginning of the flat waveform it has a little peak that then
drops down to form a flat line for the rest of the wave. This of
course repeats but in the negative direction for the negative part of
the wave. I thought you meant frequency for the time dimension but now
I think what you mean is how long does it take for the waveform to
become flat. It looks like it takes .1 mS. And the overshoot is about
30mV
Eric"

Thanks Again,
Eric