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Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. |
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27th Jan 2023, 12:22 am | #1 |
Tetrode
Join Date: Nov 2020
Location: Udine, Italy.
Posts: 59
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O_scope
Just Little question : I have connect an audio oscillator on o_scope and I see the sine...but if I change frequency by the knob of audio oscillator, the trace on the screen Is variable to left or to r right and too much Speed if increase the level of frequency on audio oscillator...why!?
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27th Jan 2023, 3:10 am | #2 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,800
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Re: O_scope
It sounds like you need to learn about the triggering system for the oscilloscope's timebase. There is material on-line and also videos of explanations. Have a search around.
David
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27th Jan 2023, 7:48 am | #3 |
Dekatron
Join Date: Jul 2009
Location: Sleaford, Lincs. UK.
Posts: 7,637
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Re: O_scope
As David says it sounds like the trigger. Learning to "drive" your scope takes some time, also your scope might not have a good trigger, some scopes are better than others.
What scope is it? Some have various trigger settings, try playing with the control settings. Andy.
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27th Jan 2023, 12:00 pm | #4 |
Heptode
Join Date: Jan 2006
Location: Cornwall, UK.
Posts: 501
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Re: O_scope
Guide to using an oscilloscope:
https://www.vintage-radio.net/forum/...7&postcount=52 |
28th Jan 2023, 12:59 am | #5 |
Tetrode
Join Date: Nov 2020
Location: Udine, Italy.
Posts: 59
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Re: O_scope
Hi,mr david_andy_simon…o_scope is Gould-250 Made uk,ths for guide very useful,now i note trace in screen not much speed ( i have rotate knob Frequency audio oscillator about 60Hz ) and haven’t change the time knob o_scope…only to command knob in oscillator audio…i think because regulation is a about 60 Hz?
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28th Jan 2023, 7:03 am | #6 | |
Octode
Join Date: Nov 2011
Location: Manchester, UK.
Posts: 1,872
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Re: O_scope
Quote:
By the way, thanks for your neologism 'knob-o-scope'. I'm going to try to remember that one and use it.
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28th Jan 2023, 10:28 am | #7 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,800
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Re: O_scope
You have a relatively modern, but very basic oscilloscope. The type used in schools and basic labs in universities. Pretty much an ideal instrument to learn on.
It's common for even fairly basic scopes to have two input channels. However, the CRT can only generate a single spot. So some trickery is needed. You'll find switches to select channel 1 or channel 2 or alt or chop. Channels could be numbered A and B or 1 and 2. I'll just use 1 and 2 for names. Alt means that it runs the trace once for channel 1 then does it again for channel 2. If you're scanning fast enough, this is fine and it then works like a 2 channel oscilloscope. If your scans have to be slow, then you see one channel's trace being painted on the screen, then the other and flicker can be annoying. Selecting chop starts a free-running oscillator switching between one trace and the other, so it looks like you have a two channel dual trace oscilloscope again, but with less flicker. Run the timebase faster and then you may start to see the chopping action between the two traces. For what you're trying to do you only need one trace, so select channel 1 and life is simpler. This puts channel 1 into Y-deflecting the spot on the screen. As Mark has explained, a free running timebase can at various settings give a display which can appear fixed, but drifts off. The solution is to have a timebase which is NOT free running. Old oscilloscopes took a sample of the signal and injected it into the timebase oscillator, relying on its tendency to lock on. This is not too reliable. So the 'Triggered timebase' was invented (By Howard Vollum, founder of Tektronix) This is a more definite system. You should have switches to select which channel you trigger from (or from a sample of mains) then a switch for AC or DC coupling (AC should be fine to start with) and a level control to set the trigger threshold, and a +/- switch to select whether to trigger when crossing the threshold in a +ve going or a -ve going direction. There is likely to be a switch to set the trigger running to 'normal' or 'auto' Normal makes the timebase halt waiting for triggering to occur. No triggers and you get no traces. You have to fiddle with the trigger controls until you find a trace. Auto makes the timevase wait for a trigger, but if one doesn't happen for well over the full scan time, it fires on off anyway. This can give you unwanted triggeredd scans when you don't want them, but those scans give you clues about how to set the trigger controls to get them working. David
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28th Jan 2023, 12:19 pm | #8 |
Hexode
Join Date: Jun 2018
Location: Buckinghamshire, UK.
Posts: 382
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Re: O_scope
Operation section of the OS250 user manual:-
Gould OS250 Operation.pdf Full user/service manual here: <LINK> Cheers |
29th Jan 2023, 2:31 am | #9 |
Tetrode
Join Date: Nov 2020
Location: Udine, Italy.
Posts: 59
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Re: O_scope
So it was the trigger that must have captured the signal of the line ... in fact I had randomly set the settings of the o_scope ... Mark's answer was essential and together with the basics that David gave me on the operation of the o_scope, it gave me more security in its use, really thank you also for the "Link" with the technical manual of my Gould
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29th Jan 2023, 2:45 am | #10 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,800
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Re: O_scope
Once you're triggering, you can move the time/division controls around and you see the waveform stretch and shrink, pinned at the lefy edge of the screen, you shouldn't get a picture that just drifts across the screen.
Play around with the trigger controls and tou'll see that they set what the signal has to be doing at the left edge of the screen, where and when the timebase is released to run. It all becomes comfortable and natural as you get used to it. David
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2nd Feb 2023, 1:03 am | #11 |
Tetrode
Join Date: Nov 2020
Location: Udine, Italy.
Posts: 59
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Re: O_scope
It all becomes comfortable and natural as you get used to it. 👍
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