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Thank you that was very useful information
just one more question, can I have an advice how to safety connect digital scope to read the coil, I have 100x probes but they home made and really noisy so I want to use 10x one and voltage might exceed them and I don't know what will happen to scope then.
Last edited by therian; - 7th December 2007 at 21:31.
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You will destroy it. A coil with the kind of inductance you are winding will probably have an emf of a few kV... most modern scopes only have a 50v tollerance.and I don't know what will happen to scope then
Use your probe set to 10:1 and use a Resistor divider chain of another 10:1. If the Bottom Resistor is 1M it won't load the circuit. That should give you a 5kV operational tollerance.
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Hi,
Pulse motor evolution. (Moto-perpetuos made in Seattle USA).
(Make sure your PC speakers are on).
Best regards,
Luciano
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Yeah, right... more like moto-preposterous...
Would be more meaningful if he showed CURRENT-IN versus CURRENT-OUT as well as the voltage which on it's own is irrelevant.
What he's trying to make you believe is that his Power-Input, less frictional losses, less conversion losses, less electrical losses, is still a NET GAIN?
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will this wok as 100:1 probes ?
------/\/\/\99K\/\/\--------------------> to scope
******************|
******************/
******************\
******************/
*****************1K (1.001К)
******************\
******************/
****************** \
******************|
----------------------------------------> to scope
all resistors 1W
what about AC is it safe for AC
I already build this probes but they so noisy, pick up all wiring
------/\/\/\25M\/\/\-------------------->to scope
******************|*****|******************
******************/*****| ******************
******************\*****|******************
******************/*****\/******************
*****************1M****--******************
******************\*****| just in case 2 zener diodes( which will newer switch because of low current)
******************/*****--******************
****************** \****/\******************
******************|*****|******************
-------/\/\/\25M\/\/\------------------> to scope
Last edited by therian; - 9th December 2007 at 02:10.
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Looks good if in your opinion 100k isn't going to adversely load your circuit.
Safety.
If you are connecting a scope to an AC supply (eg Supply Mains out of the wall), then the 0v on your scope (unless it's a Battery scope) will almost certainly be Ground/Earth. If you live in a country like the USA which controls population growth by allowing it's citizens to plug their Power Cords into the wall either way round, then you can have a situation where the scopes 0v (Earth) is being connected to the Live in your device under test.
Either...
(a) For Test purposes feed your device through a 1:1 ISOLATING Transformer (this is the preferred method as your device will no longer be LIVE - it'll still be dangerous but not LIVE relative to EARTH), or...
(b) Isolate your scope through a 1:1 Isolating Transformer (not the brightest option as your scope can then become LIVE and rubber-soled shoes and Latex gloves are then recommended).
Why then even suggest option (b)? Well your project/device just might suck 20kW and you only happen to have a 200VA Isolating Transformer!
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Yes, zapping people with Polarized 220VAC is much better than polarized 110V.If you live in a country like the USA which controls population growth by allowing it's citizens to plug their Power Cords into the wall either way round
That's right, we're Polarized now. (according to code)
err- Can you polarize 220V? They're both hot aren't they?
_
DT
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Hi,
Use wrought iron for the nucleus of the coil.
More about that here: (Read the book from page 1).
http://books.google.com/books?id=4KW...jLb0wQpLXST66c
The whole book in a 44MB PDF file.
(Scan of the 3rd edition of the book printed in the year 1900).
http://ia310925.us.archive.org/1/ite...00ewinrich.pdf
The reprint of the book in 2003:
(Same as 3rd edition of the book printed in the year 1900).
http://search.barnesandnoble.com/boo...=9781929148110
(113 years after the original book printed in 1891).
The author: James Alfred Ewing (1855 - 1935)
http://en.wikipedia.org/wiki/James_Alfred_Ewing
* * *
Why do you need to connect an oscilloscope?
Possible alternative solution to measure the strength of the coil's magnetic field:
Best regards,
Luciano
Last edited by Luciano; - 9th December 2007 at 16:14.
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