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### Topic: Finally a one Gig ohm resistor is avalible (Read 8793 times)previous topic - next topic

#### retrolefty

##### Aug 20, 2011, 07:04 pmLast Edit: Aug 20, 2011, 07:06 pm by retrolefty Reason: 1
Wonder what took them so long to make them avalible? Not sure it would be useful as a pull-down resistor for a arduino input pin.

Says useful for:

Quote

Suitable for Impulse voltage generators, arc furnace damping, energy research, pulse modulators, capacitor crowbar circuits, high voltage snubber circuits , X-ray/imaging equipment, and EMI/lightning supression

http://www.ebay.com/itm/1G-Ohm-3W-5-Resistance-Glaze-High-Voltage-Resistor-/230651855090?pt=LH_DefaultDomain_0&hash=item35b3ec00f2

I would suspect that just touching the body of this resistor and leaving finger prints on it would lower it's resistance value.

Lefty

#### Jack Christensen

#1
##### Aug 20, 2011, 07:42 pm
Cool, right up there with 1-Farad capacitors. When I was in school a prof told us that a Farad was such a big unit that a 1F capacitor would be the size of a bathtub; well not quite, as it turns out.

Old cartoon I wish I still had, engineer standing outside the door, semi-trailer backed in, driver handing him papers, engineer says, "No, no, no! I wanted ten, one-million ohm resistors!"

#### retrolefty

#2
##### Aug 20, 2011, 07:54 pm
Quote
unit that a 1F capacitor would be the size of a bathtub; well not quite, as it turns out.

Well size one needing a 100vdc rating and then you will have to clean out the bathtube to hold it.

#### robtillaart

#3
##### Aug 20, 2011, 11:36 pm
Quote
(433 Farad at 15V - 48750 Joules

Think it is time for a warning to handle these with care ...

// 4.2 Joule can raise 1 gram water 1 degree C. ==> 48750J is enough to raise 1 Liter of water 10+ degrees,
// recall a human is 70% water, so it could raise all your water with 0.2C if spreaded evenly ..
// or raise the water in your index finger far above boiling point.....
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

#### westfw

#4
##### Aug 21, 2011, 12:17 am
Moore's classic book on Electrostatics has a rule of thumb that 10J discharges can easily be fatal.
(That's for very high voltage circuits where body resistance is insignificant.  It gets more complicated when you have 48000 Joules at 15V.  Recent (and rather good) video here: http://www.youtube.com/watch?v=EoWMF3VkI6U )

#### cr0sh

#5
##### Aug 21, 2011, 02:56 amLast Edit: Aug 21, 2011, 03:02 am by cr0sh Reason: 1

Moore's classic book on Electrostatics has a rule of thumb that 10J discharges can easily be fatal.

Great video; I'm now envisioning a "micro arc-welding rig" in my future (it would cost \$70.00 for the caps). I'm wondering, though, if it's possible get stick electrodes smaller than 1/16"...

After some research - I'm now wondering if a micro-TIG rig might be possible... I must be nuts.
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

#### westfw

#6
##### Aug 21, 2011, 03:35 am
http://www.professionaljeweler.com/archives/articles/2000/apr00/0400mn3.html ??

#### retrolefty

#7
##### Aug 21, 2011, 03:54 am
Quote
It looks like you could get much more than 1F @ 100V in a shoebox with 7 of these...

Type 6 BOOSTCAPÂ® Array (433 Farad at 15V - 48750 Joules)

So if we charge a 1F cap to 100 volts through the one Gig resistor(the OP was about using this resistor, lets stay on post subject    ), how long to fully charged state?

Lets see RC time contant = (10E9 X 1) =  31.7 years to just 63.2 volts ? Is that right? that's beyond my life expectancy!

Someone younger will have to take this project on and run with it.

Lefty

#### justjed

#8
##### Aug 21, 2011, 05:18 am

Great video; I'm now envisioning a "micro arc-welding rig" in my future (it would cost \$70.00 for the caps). I'm wondering, though, if it's possible get stick electrodes smaller than 1/16"...

My landlord does this. Don't remember what size cap he's using though.
... it is poor civic hygiene to install technologies that could someday
facilitate a police state. -- Bruce Schneier

#### Grumpy_Mike

#9
##### Aug 21, 2011, 05:31 am
When I was at University on of the Lecturers (Profs in the U.S) Had a yellow warning triangle saying:-

WARNING ONE MILLION OHMS

Under which he stuck a 1M resistor

The cleaners kept clear of it.

#10
##### Aug 21, 2011, 06:18 am

Finally!  A useful poll!

#### robtillaart

#11
##### Aug 21, 2011, 10:47 am

After seeing this vid I finally know how Darth Vader uses the Force...

Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

#### udoklein

#12
##### Aug 21, 2011, 06:30 pmLast Edit: Aug 22, 2011, 05:16 pm by Udo Klein Reason: 1
Although not just as cool there are other devices with similar low series resistance. The first thing that springs to mind are car engine starter batteries. A friend of mine (student of electrical engineering working on his thesis - a charger for electrical cars) once had a set of those in series for 600V. He was talking something about "small scale current riples". When I asked about small scale he said "almost nothing, you can barely measure it, maybe 20A". They also had some nice caps >1kF in their lab. I think these were some of the very first ultra caps. These guys had those for experimenting ~15years ago-
If I remember it right they used the caps to provide additional current while the (lead) batteries where not able to deliver enough current.

#### bld

#13
##### Aug 21, 2011, 08:20 pm
I want one!!! Not sure why through...
captain-slow.dk | non contagious!

#### retrolefty

#14
##### Aug 21, 2011, 08:57 pm

I want one!!! Not sure why through...

Me neither. Part of me does, but part of me says: hell, its got +/- 50 Meg ohms tolerance, what a POS.

Lefty

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