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PostPosted: March 30th, 2020, 5:55 am 
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Joined: January 15th, 2015, 7:19 am
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Location: Baltimore MD
I found this YouTube very interesting
https://youtu.be/BnR_DLd1PDI

I hope I did not waste your time


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PostPosted: March 30th, 2020, 8:43 am 
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I did not waste my time. I will have to try this sometime.

His collection of test equipment was astonishing. Why would he need all that stuff?

ray


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PostPosted: March 30th, 2020, 8:46 am 
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I think he collects old test equipment. I saw a Tektronix 555 scope which goes back to the 1960's. Nowadays a scope, spectrum analyzer, etc. is something you plug into the usb port on your laptop.


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PostPosted: March 30th, 2020, 8:48 am 
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im thinking its not real, something virtual
anyway he is a interesting watch


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PostPosted: March 30th, 2020, 8:49 am 
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Are there any recommendations for such a usb device? Just sufficient for basic tube stuff and to do a similar test on a capacitor?

ray


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PostPosted: March 30th, 2020, 8:54 am 
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Here are a bunch of them -

https://www.amazon.com/usb-oscilloscope/s?k=usb+oscilloscope&page=3


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PostPosted: March 30th, 2020, 11:34 am 
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This is what pisses me off about internet information. Film capacitors are inherently non-polar as they are NOT electrolytics in that they do not have a formed dielectric.

They are essentially a classic (legacy if you will) capacitor dating from the first experimental Leyden jars -- having a dielectric such as paper or plastic creating a "sandwich" between metal plates.

Metalized film have the "plates" coated on the dielectric material that is wrapped.

That striped-mark on many film capacitors simply indicates the outer-most wrap. Some will say that capacitor orientation in a signal path can make a difference.

Maybe if the cap is a shunt to ground -- the cap then has a built-in shield.

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PostPosted: March 30th, 2020, 12:17 pm 
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that is exactly what the guy said and he demoed that with an oscope
I it might make a difference to have the outer wrap on the low impedance side for noise reduction


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PostPosted: March 30th, 2020, 2:17 pm 
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Pelliott321 wrote:
that is exactly what the guy said and he demoed that with an oscope
I it might make a difference to have the outer wrap on the low impedance side for noise reduction



The point I was making is that film caps are not polarized and that making that comment is very misleading.

And what would be the low impedance side? Plate or grid? Hmmm.

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PostPosted: March 30th, 2020, 3:27 pm 
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He said the plate side


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