I just saw this nice demonstration of second order linear systems. The top one is Underdamped (zeta < 1.0), the middle one is Critically Damped (zeta = 1.0), and the bottom one is Overdamped (zeta > 1.0).
If you ever wanted to see the mechanical equivalent of your Quasimodo electronic output, this is it.
The .gif video is hosted on a third party image site and I don't know how long they'll keep it before scraping it off their server. View it now while you still can: (http://imgur.com/gallery/NErmd)
I'm not too sure but I think the bottom image is a fine crystal wine glass that's been tapped with a wooden spoon.
If you ever wanted to see the mechanical equivalent of your Quasimodo electronic output, this is it.
The .gif video is hosted on a third party image site and I don't know how long they'll keep it before scraping it off their server. View it now while you still can: (http://imgur.com/gallery/NErmd)
I'm not too sure but I think the bottom image is a fine crystal wine glass that's been tapped with a wooden spoon.
How does one get the site to work?
None of the headings nor descriptions are links.
The box on the right does nothing either.
None of the headings nor descriptions are links.
The box on the right does nothing either.
Here's what I did:
- Hover my mouse over the word "gallery" in blue text in post #663 of this thread
- Right-click the word "gallery" and select "Open In New Tab"
- Click on the newly created tab
- Wait 20 seconds for the videos to load
- Watch the video just below the words "Underdamped system"
- Watch the video just below the words "Critically damped system"
- Watch the video just below the words "Overdamped system"
- Watch the video just below the words "Undamped system"
- Windows 7 + Mozilla Firefox browser
- Windows 7 + Internet Explorer browser
- Windows 7 + Opera browser
- Windows 7 + Google Chrome browser
- Windows XP + Mozilla Firefox browser
- Windows XP + Internet Explorer browser
- Windows XP + Opera browser
- Windows XP + Google Chrome browser
I also tested it on a smartphone (!) using the Safari Browser. Yes that worked too and I successfully watched all four videos.
Maybe you can take your laptop or smartphone to an internet cafe and ask one of the other customers there to help you. Show them post #663 and tell them it is supposed to play four videos but you have not been able to make them play.
The video worked for me also (and thanks for such nice example), but a simple PC issue could have explained what Andrew has experienced.
The original YouTube video from where those clips were taken can been seen at: https://www.youtube.com/watch?v=99ZE2RGwqSM At the end of the video there's a visual comparison of different dampings.
Wine glass video is also from YouTube, a clip from some Discovery tv show.
post668 link works for me Win7+Firefox+AVG
I think it is AVG that blocks sites reputed to be bad.
This is the screen I see when I go through imgur.
I think it is AVG that blocks sites reputed to be bad.
This is the screen I see when I go through imgur.
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How high a frequency should a 'scope handle to take meaningful measurements with the Quasimodo?
I'd like to assemble and play with a ~25$ DSO kit JYE Tech: DIY Oscilloscopes, DIY Kits for Hobbyists
It goes up to 200kHz. Is it high enough?
I'd like to assemble and play with a ~25$ DSO kit JYE Tech: DIY Oscilloscopes, DIY Kits for Hobbyists
It goes up to 200kHz. Is it high enough?
For audio work I suggest an analogue scope >=10MHz.
I had a very old 10MHz scope that came down to 2MHz on it's most sensitive scale.
When it became unreliable, I replaced it with a 50MHz 5mV/div analogue scope.
I now have a 100MHz 2mV/div analogue scope, just for audio work. But there are times I wish I had some of the facilities available in a DSO type. That needs a sampling frequency >500MS/s for each channel. Two channel 1GS/s is not cheap, this would be roughly equivalent to a 50MHz analogue in terms of capturing variations.
I had a very old 10MHz scope that came down to 2MHz on it's most sensitive scale.
When it became unreliable, I replaced it with a 50MHz 5mV/div analogue scope.
I now have a 100MHz 2mV/div analogue scope, just for audio work. But there are times I wish I had some of the facilities available in a DSO type. That needs a sampling frequency >500MS/s for each channel. Two channel 1GS/s is not cheap, this would be roughly equivalent to a 50MHz analogue in terms of capturing variations.
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Thank you Andrew for your suggestions. I'd definitely like a good scope but it is out of scope of my plans right now. 🙂 I could save up during a few months but that would delay my other DIY projects for that time.
For now I'm thinking of nice two little projects, the Quasimodo and the cheap DSS kit. I don't want to get a scope somewhere in-between; if 200 kHz is enough to set the snubber than I'll go for it, otherwise this project will be delayed for some time. I'll keep in mind your suggestions when looking for a scope.
So, is a 200kHz scope enough to capture the transfo ringing and set the snubber?
For now I'm thinking of nice two little projects, the Quasimodo and the cheap DSS kit. I don't want to get a scope somewhere in-between; if 200 kHz is enough to set the snubber than I'll go for it, otherwise this project will be delayed for some time. I'll keep in mind your suggestions when looking for a scope.
So, is a 200kHz scope enough to capture the transfo ringing and set the snubber?
I have a hunch that somebody might say, "I looked in the Quasimodo design note. Of all the oscillation waveforms shown there, the fastest one was Figure XXX and its frequency was YYY kilohertz."
Not all my hunches turn out to be right, however.
Not all my hunches turn out to be right, however.
I looked in the Quasimodo design note. Of all the oscillation waveforms shown there, the fastest one was Figure 14 and its frequency was ~1400 kilohertz.
This isn't a meaningful answer to my question as this Figure shows setting a RC snubber as oposed to CRC snubbers which I intend to implement.
Of all the oscillation waveforms shown in the Quasimodo design note regarding CRC snubbers the fastest one were Figure 10 & 11 and their frequency was 133 kilohertz.
So, Mark, what is the highest ringing frequency you encountered using this circuit?
Sent from my C6903 using Tapatalk
This isn't a meaningful answer to my question as this Figure shows setting a RC snubber as oposed to CRC snubbers which I intend to implement.
Of all the oscillation waveforms shown in the Quasimodo design note regarding CRC snubbers the fastest one were Figure 10 & 11 and their frequency was 133 kilohertz.
So, Mark, what is the highest ringing frequency you encountered using this circuit?
Sent from my C6903 using Tapatalk
You may wish to consult the Excel table attached to post #643, which contains data on some 10 transformers. The highest frequency there is 305kHz (column E).
Regards,
Braca
If you use a largish value capacitor you reduce the ringing frequency.
Start with a too high cap value and try the DSO and see what is detected at the sampling rate.
If the ringing ripple is easily seen and it has lots of sample points you can then try a smaller cap value.
If the detector cannot properly show the ripple then that either means there is no ripple to be detected or that the DSO is not suitable.
Try it.
Start with a too high cap value and try the DSO and see what is detected at the sampling rate.
If the ringing ripple is easily seen and it has lots of sample points you can then try a smaller cap value.
If the detector cannot properly show the ripple then that either means there is no ripple to be detected or that the DSO is not suitable.
Try it.
Hello,
If I would like to dampen an isolation transformer that is used with a measuring instrument, for exampel a function generator that has its own power transformer, should/could I shorten primarys on the iso trafo and let the secondarys of the function generators secondarys sit in circuit and measure the iso trafos secondarys connected with the gens powertrafos primarys (gen turned on but not actually on)?
If I would like to dampen an isolation transformer that is used with a measuring instrument, for exampel a function generator that has its own power transformer, should/could I shorten primarys on the iso trafo and let the secondarys of the function generators secondarys sit in circuit and measure the iso trafos secondarys connected with the gens powertrafos primarys (gen turned on but not actually on)?
That sounds like two transformers in series. The secondary of TF1 drives the primary of TF2. It sounds like you wish to connect a snubber to the secondary of TF1 / primary of TF2.
It seems like a waste of time to me, because there are no diodes in the path to provoke huge dI/dt and initiate oscillation. Nevertheless you could proceed ahead and install a snubber anyway. What could it hurt to have some resistive damping?
You would short the primary of TF1, short the secondary of TF2, and connect Quasimodo across the secondary of TF1 (which is connected to the primary of TF2). Dial the Rs until the oscillations are damped away and zeta=1. Done.
Does this do anything beneficial? I doubt it. Does it do anything harmful? I doubt it.
Thanks Mark. I was mainly thinking it could be good for on-switch current and transient reflection dampening, but maybe I should use another formula for that.
In case you are thinking of building your own Quasimodo I can recommend the kit offered by dsolodov (Dmitry). I found the board to be of high quality ENIG finish holes and also included high quality parts such as TDK's C0G.
No relation other than that of a satisfied customer.
No relation other than that of a satisfied customer.