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Re: Flat trace when calibrating probes

Posted: Mon Feb 05, 2018 7:58 pm
by adr
Thanks for all. I've ordered a few replacement components from Digikey. It'll be a few days until those arrive and I can dive back in to resolve the issue(s).

Re: Flat trace when calibrating probes

Posted: Sat Feb 10, 2018 1:10 pm
by adr
Replaced L2 with a new component - I now have a reasonable looking square wave from the test mode. See attached photo (SEN1 = 0.1v; SEN2 = x5)

One question: the voltage read out in the upper right shows 0.0v. I thought that read out was the max positive voltage but that doesn't seem to be the case.

Re: Flat trace when calibrating probes

Posted: Sat Feb 10, 2018 1:58 pm
by MNTech
I'm glad to hear you now have a working scope.

The number in the upper right is the trigger level which you set with the slider on the right side of the display.
To see the other readings press the HOLD button while the sweep speed is highlighted.

Your display looks like it is offset a little. Did you do the 0V line alignment? The 50%-50% test square wave should have equal plus and minus peak voltages when it is AC coupled.

You do need to carefully read the manual to learn all the scope's little tricks.

One command that I learn from reading posts is the Factory Value reset. A few times my scope didn't power up correctly and needed to be reset.
Press and hold the +button and the -button for 2 seconds. Then you need to do the 0 line alignment again.

Re: Flat trace when calibrating probes

Posted: Sat Feb 10, 2018 10:36 pm
by adr
Yah, there was a slight positive DC offset in that last photo. I adjusted the vertical position such that it loo balanced now - solid 1KHz square wave with a 50% Duty cycle.

Question about power supplies: I’ve been using a 9v battery but wondered if I could use the adapter that comes with the Arduino Uno. Any exoei now with that? I’m looking for an alternative to burning through batteries.

Re: Flat trace when calibrating probes

Posted: Sat Feb 10, 2018 11:21 pm
by MNTech
You can use power supplies with up to 12 volts output.