Author Topic: EEVBlog #261 Marconi  (Read 12989 times)

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Offline tecman

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Re: EEVBlog #261 Marconi
« Reply #25 on: March 23, 2012, 03:03:02 pm »
In electronics beryllium is most often found as beryllium-copper, which is a very good spring material, with the conductivity close to copper.

paul
 

Offline robrenz

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Re: EEVBlog #261 Marconi
« Reply #26 on: March 23, 2012, 03:10:59 pm »
Just a One Hung Low brand crap cordless screwdriver from Bunnings.

Dave.
Cheers.
I hadn't noticed them getting so small.
Now that they have, and Li-Ion too, I think I'll get me one.
Bosch IXO4 looks nice with it's Easy Access adapters 3Nm £39 ...
just noticed that the Black&Decker KC460LN has more torques though  5-7Nm £26 ...
Ho hum decisions decisions.  ;)

I have one of these and it has worked very well under heavy use.
http://www.amazon.com/dp/B000WI9CIG/ref=asc_df_B000WI9CIG1947795?smid=ATVPDKIKX0DER&tag=hyprod-20&linkCode=asn&creative=395093&creativeASIN=B000WI9CIG&hvpos=none&hvexid=&hvnetw=g&hvrand=4822794381295520853&hvpone=&hvptwo=&hvqmt=

Offline T4P

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Re: EEVBlog #261 Marconi
« Reply #27 on: March 23, 2012, 03:17:54 pm »
I nearly forgot to ask what is the beryllium used for?

It's got really good thermal conductivity for a non-metal.

Just to be pedantic, although beryllium does indeed have really good thermal conductivity, it is a metal.

I suspect Psi meant beryllia (beryllium oxide), which also has good thermal conductivity but is an electrical insulator.
Short question ,
Is it beryllium that is a heavy metal or does it turn into a heavy metal being a oxide of it's own product ?
Sorry , did well at chemistry while in school but none of that made sense .
 

Offline IanB

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Re: EEVBlog #261 Marconi
« Reply #28 on: March 23, 2012, 03:37:39 pm »
Short question ,
Is it beryllium that is a heavy metal or does it turn into a heavy metal being a oxide of it's own product ?
Sorry , did well at chemistry while in school but none of that made sense .

Beryllium is not a heavy metal. Nobody even mentioned heavy metals in this thread.

Although it has not been fully explained, I believe the use of beryllium oxide in that device was as heat sink compound.

The cautionary note is because beryllium is quite poisonous and must be handled with care.
I'm not an EE--what am I doing here?
 

Offline SeanB

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Re: EEVBlog #261 Marconi
« Reply #29 on: March 23, 2012, 03:46:31 pm »
Beryllium is either added to brass to make it harder, but with a larger elastic modulus. Makes it springy and able to survive many cycles of operation, but it breaks in a few cycles if actually bent. Makes a great pressure gauge.

The other use is as an oxide, where it is a better heat conductor than any other electrical insulator, and can be used in thick washers to reduce capacitance while still handling a large heat flow. Thus you can have good high frequency response with high dissipation, good in RF amplifiers. Drawback is that the dust is a carcinogen, and it is very bad if inhaled. Normally you can tell a beryllia washer by it being a pale pink colour, as shown in the video. Nice washers, no need for heatsink compound in many cases with smooth surfaces, just a thin coat of silicone grease, but you do need to be very careful not to exceed the recommended tightening torques on them. Brittle buggers though if mishandled.
 

Offline wkb

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Re: EEVBlog #261 Marconi
« Reply #30 on: March 23, 2012, 03:49:14 pm »
Short question ,
Is it beryllium that is a heavy metal or does it turn into a heavy metal being a oxide of it's own product ?
Sorry , did well at chemistry while in school but none of that made sense .

Beryllium is not a heavy metal. Nobody even mentioned heavy metals in this thread.

Although it has not been fully explained, I believe the use of beryllium oxide in that device was as heat sink compound.

BeO is used for isolation in e.g. HF powertransistors.  And today I have received a 150W 50ohm BeO-isolated resistor that is destined for a HF dummyload.

In dustform BeO is harmful, see for more info: http://en.wikipedia.org/wiki/Berylliosis

So do not indiscriminately grind down things you do not know much about....  Yes, that also applies to the EEVblog teardown-ers around here!
 

Offline T4P

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Re: EEVBlog #261 Marconi
« Reply #31 on: March 23, 2012, 04:27:34 pm »
I always knew that if a metal was harmful , it's a heavy metal .
But it looks like in dustform it's a carcinogen ,
But when ingested it is a carcinogen too .
But yes , beryllium is a heavy metal ,
http://www.osha.gov/SLTC/metalsheavy/index.html
 

Offline Lightages

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Re: EEVBlog #261 Marconi
« Reply #32 on: March 23, 2012, 04:51:06 pm »
Beryllium is NOT a heavy metal. It is #4 on the periodic table. It is classified as an alkaline metal. The link provided  for OSHA has the word "heavy" in the url, but beryllium is included in the list as a toxic metal only.

Beryllium is a commonly used alloying agent for copper and aluminum. It adds strength and raises the melting temperature while also raising the high temperature strength of the alloy.

It is believed that Beryllium in its pure form is quite toxic if inhaled in dust or powder form and there have been reports of people dying within days of this kind of exposure. If it is contained in an alloy it is generally accepted as safe to freely machine in an open environment. If one is machining Be in its pure form then many rather strict safety procedures are to be followed.

In one of my earlier lives I had the need to know such things as I was designing equipment that made use of Be and other rather uncommonly used elements.
« Last Edit: March 23, 2012, 04:56:50 pm by Lightages »
 

Offline T4P

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Re: EEVBlog #261 Marconi
« Reply #33 on: March 23, 2012, 05:30:51 pm »
Beryllium is NOT a heavy metal. It is #4 on the periodic table. It is classified as an alkaline metal. The link provided  for OSHA has the word "heavy" in the url, but beryllium is included in the list as a toxic metal only.

Beryllium is a commonly used alloying agent for copper and aluminum. It adds strength and raises the melting temperature while also raising the high temperature strength of the alloy.

It is believed that Beryllium in its pure form is quite toxic if inhaled in dust or powder form and there have been reports of people dying within days of this kind of exposure. If it is contained in an alloy it is generally accepted as safe to freely machine in an open environment. If one is machining Be in its pure form then many rather strict safety procedures are to be followed.

In one of my earlier lives I had the need to know such things as I was designing equipment that made use of Be and other rather uncommonly used elements.
Aw man ... poor me didn't read.
 

Offline Neilm

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Re: EEVBlog #261 Marconi
« Reply #34 on: March 23, 2012, 05:41:32 pm »
Pardon me barging into this thread but what price tag would such a piece of kit have had on it?

Who would have bought one and for what purpose?


I have seen quotes for that sort of signal generator of upwards of £15k new (for the options we wanted).

I was trying to replace a signal generator that is even older than that one. Unfortunately, we did manage to get the old one fixed so no new toy to play with :(

The sig gen is used in our in house EMC testing facility. We do in house testing on all our equipment.

Neil
Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe. - Albert Einstein
 

Offline w2aew

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Re: EEVBlog #261 Marconi
« Reply #35 on: March 25, 2012, 01:38:14 am »
British Engineering at its best!--Although they did have to put in a bit of quirky design with the cutouts that don't allow you to reach the screws!

The mechanical engineer was probably coming from the British automobile industry :)

No, I don't think so - there wasn't a puddle of oil under it!
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Offline SeanB

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Re: EEVBlog #261 Marconi
« Reply #36 on: March 25, 2012, 09:52:04 am »
No, it judt means the oil ran out a while ago........

Kind of like flying on a Dakota - no oil do not get in, because it has all left. Thick like treacle syrup before flight, thin as water afterwards. To refill you might need a putty knife to help it pour from the cans.
 


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