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Topic Title: Weekend Quiz.
Topic Summary: What Am I?
Created On: 13 May 2018 11:45 AM
Status: Read Only
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 13 May 2018 11:45 AM
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Zoomup

Posts: 4692
Joined: 20 February 2014

I can be found in modern R.C.B.O.s. and other devices.

I have an inter-granular ceramic layer.

I am sealed like an epoxy egg.

I am connected to sticking plasters.

I am protective.

What am I?

What is my function?

Z.
 13 May 2018 12:15 PM
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Weirdbeard2

Posts: 447
Joined: 29 November 2017

Hi zoomup, that is sufficient enough questions to be worthy of an IET Wiring matters article!

http://www.theiet.org/forums/f...AR_FORUMVIEWTMP=Single
 13 May 2018 12:37 PM
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Zoomup

Posts: 4692
Joined: 20 February 2014

You seem to be quick on the negative star vote down button W2.

Z.
 13 May 2018 01:08 PM
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Weirdbeard2

Posts: 447
Joined: 29 November 2017

Originally posted by: Zoomup

You seem to be quick on the negative star vote down button W2.



Z.


It's not me, I would give any topic I reply to 5 stars if I had time to waste on rating topics
 13 May 2018 11:28 PM
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kellyselectric

Posts: 325
Joined: 22 July 2016

Well thats an interesting set of clues at the moment I cant figure it out il try again tomorrow
 14 May 2018 12:51 AM
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mapj1

Posts: 10897
Joined: 22 July 2004

zinc oxide is used in plasters to plasticise the rubbery sticky adhesive on the fabric. It is very mildly anti-bacterial, but is nowadays not normally used on the dressing part of an ordinary plaster, there are better chemicals for that, though in the past it was.
Also turns up in some treatments for athlete's foot.

In a fired ceramic with zinc oxide you can make device that is sometimes called a solid state spark gap, the varistor. Nowadays not just pure zinc oxide, so they tend to be called 'metal oxide varistors' and can be tweaked for various voltages.
an I/V curve that tends to slice off over-voltages, hence the use to protect delicate electronics



more deskription here

-------------------------
regards Mike
 14 May 2018 09:30 AM
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Zoomup

Posts: 4692
Joined: 20 February 2014

Yes, Mike has got it. I was thinking of a Metal Oxide Varistor that protects delicate electronic components from high Voltage spikes on the mains. They conduct when a certain Voltage is applied and reduce that Voltage by converting it into heat thus producing a deliberate Volt drop across the supply. They are a little electronic device shaped like a pill with two legs and are sealed by an epoxy resin shell. They can be confused with capacitors on a circuit board. They are normally connected parallel to any load. You will find them in R.C.B.O.s to protect any electronics like the operating or time delay electronics from lightning or inductive load produced Voltage surges. A MOV rated at say 260 Volts would be used to protect stuff rated at 230 Volts normally. Thanks Mike.

Bye,

Z.
 14 May 2018 10:57 AM
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mapj1

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Joined: 22 July 2004

bonus question for you Z, , when heated pure zinc oxide it changes colour as the electron orbitals re-organise themselves and oxygen leaves or returns - think like sheep on the motorbike in wallace and grommit
. , - from what colour to what colour?
Personally I disagree with the text book colour...

-------------------------
regards Mike
 14 May 2018 08:22 PM
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Zoomup

Posts: 4692
Joined: 20 February 2014

Originally posted by: mapj1

bonus question for you Z, , when heated pure zinc oxide it changes colour as the electron orbitals re-organise themselves and oxygen leaves or returns - think like sheep on the motorbike in wallace and grommit

. , - from what colour to what colour?

Personally I disagree with the text book colour...


Well Mike, I did not know the answer without looking it up. I think that zinc oxide powder is originally white and then turns yellow upon heating, then back to white when it cools. http://www.youtube.com/watch?v=cEIujFx2Mro

Bye,

Z.
 14 May 2018 09:30 PM
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mapj1

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Joined: 22 July 2004

Indeed. Though I see the colour as an iceberg lettuce sort of green when in the lab, as it seems do a significant fraction of blokes
(based on a sample who work in labs anyway...) On camera I agree it just looks yellow.
Colour changes about 700-800C, so you can use it to give a slightly early warning of your aluminium containment about to melt.

-------------------------
regards Mike
 15 May 2018 09:40 AM
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UncleFester

Posts: 70
Joined: 04 April 2006

Zinc oxide - takes me way back to a scene in Kentucky Fried Movie...
 16 May 2018 06:24 PM
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mapj1

Posts: 10897
Joined: 22 July 2004

Ah yes, not actually all true of course, but very funny and mockumentary.
For those who missed out on the '70s"chemicals play an important role"

from that film..

-------------------------
regards Mike
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