Electronics cheap grounding solution?

if i were to buy a short 3-pronged extension cord, cut the power plugs, and just left the ground, could this be a grounding source?

i just fried my N64 mobo that i'm trying to portibilize, evidentally they are very static sensitive.

i plan on just connecting the ground plug, strip that wire, then solder it to a cookie sheet (one with bare metal, maybe i would use aluminum foil in a pinch) to make a grounded sheet.

would this do anything bad if there were other active components on that same circuit? the only place for me to plug in is on a surge protector, but it has my iron and my work light plugged in too. i have an aversion to dying. if i take someones faulty advice and i die i'll come back as a squirrel and run up their trouser leg. [/M*A*S*H reference]

 

It's best not to use the earth pin of an electrical outlet for this, a radiator or tap or anything like that will be grounded so you can connect a wire to one of those.

 

but i don't have anything like that nearby, the only thing other than my grounded surge protector is my computer, can i do anything with that?

 

The ground on the outlet would be fine. When I do stuff with electronics most of the time I just grab the end of my USB cable for my camera, since the plug is grounded. Quick way to dissipate static.

As long as you have a good ground line, you will be fine using the house groud. If that breaks, and you have somthing leaky, you *could* get buzzed, or you could just float at that voltage. I wouldnt worry about it that much though. the ground wires dont typically have that much stress on them.


If you wanted to you could get a 10' copper grounding rod, and run a separate ground for tinkering with electronics, but that would definitely be overkill for anything other than a workshop.

The best thing I would think you could do would be to put a humidifier in the room. The humidity would help reduce static.

 

i got some nine inch nails in my garage, could i just put a couple of those in the ground and solder some wire to them? i have a window right by my "work" desk, and i could feed a wire through the screen and to my cookie sheet

 

umm, you might wana REALY check out http://hardforum.com/showthread.php?t=812518
because basicly, your all wrong

 

9" would probably be a bit short for a proper ground, probably ok for a static ground.
One thing to worry about though, "real" anti-static mats also have a 1 megohm resistor in series with them. That keeps them from being a shock hazard if you become electified. That would also suffice if your ground wire broke, and the line became hot. With 220 vac, you would only get 220 µA of current through that. Nothing dangerous at all. You might not even feel that. Grab a 1M resistor, some wire and a plug, and you'll be fine. That would even be more portable than a ground steak and a lead.

 

Yep, the series resistor is important.

Especially if your wall socket is wired wrong

 

Ground to the ATX shield of your mobo. As far as the circuitry is concerned it doesn't get any groundier. That also takes care of the situation where the computer is sitting isolated and is charged itself. If the mobo is installed into a proper chassis you can also ground to that.

As mentioned earlier, the resistor is the important part. You don't want to hit any ground on your system with a several kV pulse. If you want to be anal about it, get a 100MOhm to 1GOhm resistor. Hold one end and touch the other end to the ATX shield. After about 5 seconds connect yourself with a copper wire from a wetted part of your skin to the ATX shield. Now you are perfectly in sync with your mobo.

 

1GOhm? I don't know if that's a standard easy to find value.

I think 10M is what's normally used in wrist straps, it's also one of the largest common values.

 

I had an ESD class in school, i read industrial electrics.

The standards say you should have between 1Mohm and 10Mohm between all objects and earth, most ESD protection devices connect in series with little button fastenings or banana plugs and have a 1Mohm resistor. This means you cannot have more than 10 in series before you go outside the standard 10Mohms that the standard sets.

What i use thou, is i connect the machine to a grounded outlet, turn off the switch on the power supply and then when i work, i am allways touching the case, and i have never had any hardware faliure that i can relate to ESD.

The thing about shocking yourself only applies when working with live 110-500V and you need protection from making a connection through ground by the wriststrap och ESD mat. It will allso prevent electrical fire that could occour if an open connection grounded through a mat without the resistor. Don't think you are completely safe just because you have the wrist strap thou, you can still kill yourself while working on higher voltages.

The resistor is allso used to safely discharge ESD charged up in the work object when you put it down on the workmat instead of discharging it in a spark to ground.

 

I just hold onto a grounded point (such as my bench PSU) when I'm handling ESD-sensitive electronics. In all my years, I've never damaged anything with ESD.
Do note that human skin is too moist to actually generate much ESD and is conductive enough to to easily conduct ESD (which is why holding onto the computer case or using a grounding bracelet virtually eliminates ESD). However, hair can easily generate a lot of static, so tie back long hair when working on electronics.
BTW, a friend of mine (Whitney) says that she feels the safest when working with very expensive equipment by taking off all her clothes. I say that it's totally unnecessary from experience, but I guess that Whitney is very cautious with expensive equipment.

 

Just a couple of points:

One: ESD is MASSIVELY overstated. If a device fails, 90% of the time it is due to other reasons. I regularly work with digital electronics, take almos no precautions, and have yet to have any device fail on me due to ESD. Also, i have several friends who have spend 30+ years working with electronics, have degrees in electrical engineering, and agree with me.

Second: There is no real true ground. Essentially, voltage is a measure of the potential between two conductive objects. The earth is just the biggest object around, and is therefore called ground. If you tough the case of a computer, you are equalising the electerical potential between you and the computer. This also means that if a computer, is ungrounded, and you ground yourself, there can still be a potential voltage difference between you. The reason ytou are told to unplug you computer when working on it is due to worry of power supply failure, therefore connecting yourself to the mains voltage. It is almost safer to work on a computer while t is connected to a grounded outlet.

Overall, most of the stuff about ESD is written by people who worry about being sued if they do not post warnings about ESD, and something, somehow, goes wrong (unlikely) and someone gets injured, and by people who read information put out by the previous and believe it.


The easiest way to avoid worrying about ESD is to simply touch your computer case before working on it. If you are actualy working on the components, it is likely that some part of you is in almost constant contact with the case.

THings like an ESD wristband are nice, but only mildly useful if you are working in dry climates, or things like FETS, or other super sensative devices (though most have built in ESD protection these days).

 

i'm working on a N64, it has a plastic case.

it worked when i had it in the case, i took it out and handled it a few times (with socks on on carpet ) just holding the sides (i thought that would be ok, y'know, not touching the traces) and then it didn't work. the red LED wouldn't even turn on

 

Do you have proof of that? Most ESD damage does not show up immediately, it can take anything from hours to years for an ESD damage to show.

This information is from one of the companies that discovered and researched ESD back in the time when semiconductors were shipped stuck into styrofoam blocks. They made military anti-tank robots, and the units worked after assembly, but they started getting problems with a lot of them failing when they were re-tested after a few years in storage.

You forgot to say that the case has to be grounded for that to work properly.

 

Even if the case is not grounded, touching it will equalize the charges. How do you think NASA gets rid of ESD when working with electronics in spacecraft that is far away from any ground? They just treat the spaceship itself as a ground. The charges generated by friction as the spaceship is launched do not cause any problems as long as they are equalized.

 

That depends a little on the mass of the object you touch, and it works way better if the case is connected to electrical ground because then it is neutral to most of it's environment.

 

Read the Post!!

Also, most devices are most ESD sensative when alone (eg... Single ICs, transistors, etc...)

Typically, just being in a populated PCB provides a measure of protection (PCB traces havew a higher capacitance, and the other components tend to help distribute the charge, acting something like a piece of anti-static foam in and of itself.

Incidentally, the metal shielding around the internals is to keep EMI (electro-magnetic interference) from getting out, not from getting in. Many national authorities like the FCC require that a a device but out a certain ammount of EMI or less. The metal shielding helps meet that requirement. It also lets the people designing the product be more relaxed about PCB design, without having to worry about interference, going either way.

Also,

As i said, there were ESD problems in the old days. However, most everything has build in ESD protection on the die of the chip recently. Also, improvements in chip design and production has served to help make components more resistant to overvoltage, including ESD.

As for your n64, I'm not a monster, it sounds like you connected something incorrectly. Typically, the power led is just connected between ground and V+, with a resistor in series, which is practically indestructable, from an ESD perspective.

Check the outputs of the power supply, and that all of the internal connectors are wired correctly. The transposition of a wire CAN destroy stuff in short order.

 

ESD protection is better, but it can't block unlimited ammounts of ESD, it is still possible to damage electronics with ESD. Especially low voltage highly complex components like CPU and RAM, but some of the new type of high intensity LED are very sensitive to ESD in the reverse direction since the specified reverse breakdown is at 5V and a few microamps.

 

Point, but it is still highly specific.

As you said, How often are you around "unlimited ammounts of ESD"?