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Question about the threat Electrostatic discharge damaging my componen

Last response: in Components
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September 21, 2011 1:19:48 AM

I was reading my PC book where it talks about the danger of static electricity. I began to read the part where it says "A monitor can also damage components with ESD. Do not place or store expansion cards on top of or next to a monitor, which can discharge as much as 29,000 volts onto the screen."

Now I have my monitor on a desk right next to my desktop computer. And I'm wondering if, when I turn on the monitor does it cause damage to the parts from my computer without me even knowing? It's like 4 inches away.

And I have my TV to the left of my computer monitor also, when I have my TV on, and I turn my monitor on that interference effects the left side of the TV for about 3 seconds. So I don't know if it damages the TV. The TV still works. I just think the minute I turn on my monitor that interference effects it. I don't know if it has damaged anything.

My PC book also states that ESD (electronic discharge) damage can (if it's upset failure), be difficult to detect because they are not easily observed. But it would still work but not perform well.

So if ESD really did damage my computer (because of my monitor is only 4 inches away from my PC). Would I know it? Or am I making a big deal of this?
September 21, 2011 1:47:36 AM

If you were to actually see or hear static discharge from the monitors to the PC then it could be an issue, but in all likelihood you are fine. Electronic hardware damage from static electricity happens more frequently when a person touches a mobo or circuit board when they have static electricity built up from their clothes or carpet or whatever. That is why you are suppose to wear a ground strap when working on electronic equipment. The ground strap allows the static to discharge to ground (earth) and not shock the electronic components and damage them.

The only way you might know if ESD damaged something is if it doesn't work and you saw or heard the ESD snap.
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a b C Monitor
September 21, 2011 2:51:54 AM

You cant damage a computer by static shocking the out side metal box. This is because the electrons will always travel on the out side edges of the metal and will never enter the inside of the box. Have you have been to the Boston Museum of Science? Some dude sits in a metal ball that gets wacked with lightning.

http://www.mos.org/sln/toe/cage.html

The same principals that protects that dude protect the insides of your PC. It is also why being in a car is a safe place during a thunder storm.

The A+ instrcutions say to touch the metal computer case to discharge any static before you crack the case.
Now if you shocked an exposed board or stick of ram then there is a very real threat of damage.
You have nothing to worry about.
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a b C Monitor
September 21, 2011 2:53:23 AM

(1) The so called arc that you see or hear are for voltages generally above 1 KV. it takes much less to damage a low voltage IC.

(2) I think you will find that the Monitors the artical is referring to are the OLD Cathode Ray Tube (CRT) monitors. Even when turned off the high voltage coating can build up a large enough voltage to sit you on the floor if you touched the A+ lead. And NO it is not a good idea to leave circuit cards sitting exposed next to a 30 inch color CRTThis is NOT a problem with todays LCD monitors.

On that 29KV, that was generally for a 30 inch color CRT, A 20 in CRT is probably only around 18KV. NOTE this is the voltage surrounding the sides of the CRT (On the Inside) and is the voltage used to Accelerate the electrons from the cathode to the phosphor on the face of the crt. This coating builds up a charge and holds it even when turned off.

Know for the part that some do not realize - You do not have to touch and draw an arc to damage some electronic components. There is an EM field that surrounds an electric charge, This emf can induce a voltage and damage the component.

PS Decreased performance and delayed failures due to ESD are referred to as "Walking wounded"
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September 21, 2011 4:32:38 AM

bucknutty said:
You cant damage a computer by static shocking the out side metal box. This is because the electrons will always travel on the out side edges of the metal and will never enter the inside of the box. Have you have been to the Boston Museum of Science? Some dude sits in a metal ball that gets wacked with lightning.



I'm a little worried now, I've actually had my case open for a while. Just to keep it cool. So does that mean it can be damaged? Because the case is open.



RetiredChief said:
(1) The so called arc that you see or hear are for voltages generally above 1 KV. it takes much less to damage a low voltage IC.


I do have a circuit card hooked up to my motherboard 10 inches away! I'm surprised its not damaged or maybe it is? The motherboard is about 14 inches away.

RetiredChief said:
(2) I think you will find that the Monitors the artical is referring to are the OLD Cathode Ray Tube (CRT) monitors. Even when turned off the high voltage coating can build up a large enough voltage to sit you on the floor if you touched the A+ lead. And NO it is not a good idea to leave circuit cards sitting exposed next to a 30 inch color CRTThis is NOT a problem with todays LCD monitors.

On that 29KV, that was generally for a 30 inch color CRT, A 20 in CRT is probably only around 18KV. NOTE this is the voltage surrounding the sides of the CRT (On the Inside) and is the voltage used to Accelerate the electrons from the cathode to the phosphor on the face of the crt. This coating builds up a charge and holds it even when turned off.


Then actually I do have a problem, Mine is a CRT 19.5 inch (Gateway VX1110). A huge monitor, and its very heavy. For now, I hope I dont have any damage. I'm going to close my computer case then.


What's interesting is that this is a problem I never heard before that you cant have a monitor next to a computer. Maybe I'm over reacting, although.
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September 21, 2011 4:43:40 AM

No the static shock would have to arc to an electronic component not the case. The case is grounded via the 120V power cord. Close proximity only matters if the arc goes to the elctronics not if it arcs to a gground other than the electronics - such as you.
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September 21, 2011 4:53:20 AM

beenthere said:
No the static shock would have to arc to an electronic component not the case. The case is grounded via the 120V power cord. Close proximity only matters if the arc goes to the elctronics not if it arcs to a gground other than the electronics - such as you.



I see, so what you are saying all the electronic devices in the computer case is grounded and can't be affected at all. Yeah, I'm trying to study about this stuff. And this is my weak point. I'm still having trouble understanding "Ground", "Arcs".

I assume a "Ground" is what releases the excess static electricity into the ground? Otherwise if there is no ground then the static electricity has no where else to go except into me or the device.
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a b C Monitor
September 21, 2011 1:32:47 PM

First, let me dispel your concerns. Having your system (computer with side panel open and within 10 in of a 19 inch CRT poses NO problem. The article you read pertained to laying an unprotected circuit card (NOT in its protective ESD bag) close to a CRT monitor. I would not lay your USB thumb drive on the top of a CRT monitor -LOL.

Now to dispel some miss information.
(1) A “visible” arc is simply the ionization of the air this is caused when the voltage potential exceeds the ionization required for the air molecules to omit light. Example in a neon bulb the voltage required to ionize the gas is only (if memory serve me right) about 76 Volts and when the voltage across the electrodes exceeds that the bulb give off light and passes current. For air it is much higher I think, without looking up is in the KV and depends on the distance between the two points.

(2) YOU DO NOT HAVE TO DRAW AN ARC to damage a component. When two objects are at a potential difference there is an electro static field between them. The strength depends on two factors: the potential difference and the distance between them. Distance is important as the strength is inversely proportional to the square of distance. IE double the distance and the field strength is reduced to ¼ of original value. While everyone knows that if you draw an arc to a pin, other than ground, you can destroy/damage the component. What is missing is YOU do NOT have to touch the component, or draw an arc!!! Summer and High humidity reduce the ability to build up a charge. Winter time and Relative humidity (RH) of 30% and less allow the body to build up a charge very quickly!! If you have built up a charge, you HAVE an electric field that can induce a voltage in a component. Here is an example: You just received a new memory module and you pull it out of the package. You are very careful to NOT touch the edge connector, RH is 20% (winter time) – You can still induce a voltage that will damage one of the memory chips just by bringing your fingers very close – NO ARC, NO CURRENT, but you induce a low voltage say 20 Volts between two adjacent cells inside the memory chip package. OPPS, they operate at 1->2 volts. Case in point: The AF had a system that measured runway visibility, I dubbed it a Lighting detection system – If they had a lightning strike 5 Miles away the EM pulse would wipe the system out.

(3) You asked about ground. A ground is simply a point that has the ability to absorb or give up enough electrons so as not to take on a voltage level. Normally a ground is connected to earth ground, but not always as a car is NOT tied to earth ground but has a very large mass of metal. For a computer case it is tied to earth ground thru the 3rd wire on the AC input. Under normal conditions the metal case is enough to be considered ground when not plugged in, But NOT always. Case in point, again worse case, winter time and you have built up 20 KVs (AND YESS that is possible) you touch the case that is not connected to earth ground – What happens is you simply transfer electrons to the case to neutralize the potential difference between you and the case. The case is now charged to 10 KV UNLESS it has a path to earth ground. This then creates a potential difference between the case and ALL the grounds inside the case. During this last winter there were several post where people have drawn an arc to the case (Close to the USB front panel ports) and Killed the USB chip on the mother board. This was limited to only a few cases and poor shielding and/or the individual arced to one of the pins on the USB port.
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September 22, 2011 2:13:59 AM

Alright, RetiredChief, I appreciate your input and, everyone else.
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September 22, 2011 2:14:48 AM

Best answer selected by Scribels.
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