what's the point?

Retromaster · Post by **Retromaster** » Tue Jan 30, 2007 7:19 pm

peoples.....just what is the point of ground?
I notice it in 2 forms-
1- when I was tinkering with my computers fried power supply I noticed a wire coming off the 3rd prong of the power cord that lead directly to the metal of the power box's casing. Why?
is it to keep yoo from shocking yourself?
I also notice it as refered to negative wires.
I see ground wires in some project all going to a common metal place.
Why peoples? Why...?

Kurt_ · Post by **Kurt_** » Tue Jan 30, 2007 7:37 pm

It completes the circuit and lets electrons flow freely.

Electricity (in a battery) is a chemical reaction. There are 2 electrodes undergoing a chemical reaction. One gets oxidized and the other one gets reduced. (Gains electrons from the other electrode, and loses them to the other-other electrode, not respectively.)

This reaction will occur if you put the two electrodes in the same container, with a conducting liquid. Electrons are transfered to and from the electrodes.

BUT If you seperate the two metals, putting them in their respective salt solutions (Zn would be in Zn(No3)2, for example) and add a wire in between the electrodes, the electrons travel through the wire, to the other electrode and such.

By adding things in the middle of the wire, the electrons undergoing the reaction do work. But if you don't connect the wires (or add a connection to ground) then the electrons simply undergo a reaction in the solutions.

Don't know if that makes sense. But if you want to know more about this I can grab my skimpily-information-ed chem notes.

Rekarp · Post by **Rekarp** » Tue Jan 30, 2007 7:39 pm

The metal areas are usually (if not in all cases) are a common ground for the system. Its just a convenient spot to have your ground.

vskid · Post by **vskid** » Tue Jan 30, 2007 7:49 pm

Grounds are on appliances and computers with metal cases (on others too, but on pretty much anything with a metal case). Without a ground, if something in the appliance shorts to its case and you touch it, you get fried. With a ground, if something in the appliance shorts to the case, it goes to ground and flips the breaker, saving you a great deal of pain.

Kurt_ · Post by **Kurt_** » Tue Jan 30, 2007 7:50 pm

Oh, and the ground on your power box thingie goes into the ground. It's not called ground for nothing.

Just with portable electronics, they kept the name and it refers to the negative end (or reduced electrode) in a battery.

timmeh87 · Post by **timmeh87** » Tue Jan 30, 2007 9:00 pm

ground is the reference point to which all voltages are relative to.

Retromaster · Post by **Retromaster** » Fri Feb 02, 2007 9:06 pm

I respond late for two reasons-
theres a new lock on my pc that has something to do with my parents....

I couldn't get on 'cause gannon or ben was messing with phpbb2 and it said- "the page is currently unavaible. try again later."

So ground is also a term for negative, and is used so static does not occur?
BTW, timmeh87, you're a genius.....

timmeh87 · Post by **timmeh87** » Fri Feb 02, 2007 10:38 pm

ground is just a huge place where space static electricity can go safely. static still 'occurs' persay, it just doesn't blow anything up inside.

theres also a subtle difference between ground and 'earth ground'. the difference being mostly what i said before about voltages.

Retromaster · Post by **Retromaster** » Fri Feb 02, 2007 10:45 pm

I heard about earth ground and chasis ground in text book. whats the difference between those you wonder?

timmeh87 · Post by **timmeh87** » Sat Feb 03, 2007 12:12 pm

do i wonder or do you?

ground, or chassis ground is the ground everyone talks about around here, its the ground thats on the negative terminal of your battery, and its the ground that you measure all voltages relative to. (and also the one connected to shielding to stop interference)

earth ground is literally that, its an electrical connection to the.. ground. the dirt beneath your feet. it is useful for things like static discharge, lightning rods and antennas. copper pipes are usually grounded to the earth.

of course, in some situations, you may find that these two things are connected together, for example, three phase power sometimes uses the earth as the neutral conductor, IIRC (i saw somewhere that this was causing a problem with cows in fields getting electrocuted...). however, in portables and they are not.

Post by **gannon** » Sat Feb 03, 2007 12:39 pm

timmeh87 wrote:this was causing a problem with cows in fields getting electrocuted

Can't help but kinda laugh at that

I remember the last time I was electrocuted on AC...thanks to the chassis ground I was only getting zapped at 30Hz

Retromaster · Post by **Retromaster** » Sat Feb 03, 2007 1:53 pm

back before I was into this stuff I tried to make a lamp by plugging an old power cord to a lightbulb directly. it was kinda stupid, i know, because I lost a few braincells, which is why I guess people think im stupid....this was only about 4 years ago.....I hadn't even heard of transformers. or resistors. so now im granting only one time for any of you to say this in my thread- "RETROMASTER YOU GODDAMN RETARD!" its true, go ahead. say it. especially you harshboy.....
if I had grounded it, would I have lost less braincells? or the same amount?