How do I use an antostatic band? I was told that it is supposed to be put around the wrist and the terminal is connected to the ground point of the PCB one is working on.

What do I do while I am working on a general purpose PCB? The ones with mant holes and copper pads?

And can it prevent damages to the IC while I pick it up? How do I balance the potential in this case?

Thanks.

__________________
Bharath Bhushan Lohray.
M.Sc. Electronics.

 

You connect it to ground, you could also connect the PCB to ground as well, or more commonly have it sat on a conductive mat that's connected to ground.

Bear in mind, none of these are direct connections, they include high resistances - sufficient to discharge static, but high enough not to pose a safety risk.

Don't get too carried away with anti-static precautions, they are only occasionally required, most components are safe without them!.

I occasionally use one at work (mostly while replacing laser assemblies), but have NEVER used one at home, and never had any static problems.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Electro-Static Discharge (ESD) is taken very seriously in the electrinics industry, with many £££ $$$ spent on preventing damage to semiconductors.

Have a look here for some more information.
www.minicircuits.com/appnote/an40005.pdf

Unlike Nigel, I do have a wrist strap at home. It is plugged into an earth terminal on the front of a piece of test equipment which is earthed via the mains plug.

And also unlike Nigel I HAVE LOST expensive components to ESD until I realised what was happening.

JimB

__________________
Experience is directly proportional to the value of the equipment ruined.

 

You're probably rich and have carpets? :lol:

But static does depend a GREAT deal on the environment, and on the particular person, plus what you might (or might not!) be wearing.

We had BIG problems with a guy at work a few years ago, everytime he got out of his van he could generate six inch sparks from his finger to your nose!. Now that's a prime candidate for an earth strap!.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Last I checked, Derbyshire wasnt in a dry desert like india...:-D

 

What's 'dry' mean? :lol:

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

dry desert ? :x :x :x

India contains one of the hottest places.. The temp in Bengol reached 50 deg this summer. And Mausingram and cherapunji are the rainiest places in the world. India is a country of varied topography.

:?: Does the static band contain the high resistance components or do I have to put an extra resistor or something?

I purchased a band but do not know how to make the most of it. I dod lose two 6116 RAM chips to dont know what.... Static probably...

:?: So can the wrist band save an IC from being damaged as I hold it in my hands or is it only for circuit boards?

:?: is it a risk if I connect the end of the wrist band to the ground of the tree pin point?

__________________
Bharath Bhushan Lohray.
M.Sc. Electronics.

 

Normally there is a 1 Megohm resistor in series with the lead. The band itself is just a metal button, held in place against your wrist, by elastic. If you're uncertain, just measure the resistance between the band and the end of the lead. If it's low, solder a resistor somewhere in the middle of the lead.

 

The entire idea of killing off ESD is keeping everything at the same potential ... the equipment you're working on, you, the replacement parts, soldering iron, etc. This can be done without any special equipment if you simply use common sense as you work. You have a RAM to install. First, you pick up the sleeve/bag the RAM comes in. That puts you and the bag at the same potential along with the RAM inside the ESD bag/sleeve. You remove the RAM, no potential difference, no damage. Then with the other hand, you grab the chassis of the computer. Now you, the computer and the RAM are at the same potential, no damage. You install the RAM. You're done, no damage.

The static free workstations, ESD mats, wrist straps, etc. are for forgetful folks or assembly lines where speed is paramount in saving money. If I used all the ESD stuff all the time, would I damage fewer parts? I don't know. I've never damaged one without it unless I did something stupid. And that's where the "forgetful" part comes in!

One warning that was alluded to in previous posts. Never, ever ground yourself directly with a wrist strap. Always make sure that there's no less than 1M ohm in series with the strap and ground. If Nigel were to wear a wrist strap without that resistor, he'd kill himself if he touched the chassis of his oscilloscope.

Dean


Dean

__________________
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).

R.I.P.