What precautions against electrostatic damage do you take?

[hank]

I'm curious, having for a long time done minor computer repair on static-sensitive old Apple laptops - and having met quite a few people who blow off the problem rather than taking ESD precautions (grounded work surface and wrist strap, basically, are all that's needed).

ESD doesn't usually kill a semiconductor -- what changes is a threshold, putting the component a bit out of spec. A repair tech working away for a while without proper static protection can put a lot of components a little bit wrong.

Nichia's white LED tech specs have not just the standard information on precautions, but also a specified test procedure to be used after an LED is mounted in final quality control, to detect any minor damage from ESD that may have happened.

Now that's for industrial and life-safety quality, where a premature failure of a LED could lead to serious and expensive damage.

But I'm curious -- how much are y'all thinking about this while handling LEDs? Do you have and use antistatic mats and wrist ground straps?

Years ago I was given the ESD "Pop Quiz" question --- Can you give two good reasons why there is a resistor in an antistatic wrist strap?

 

[star882]

The resistor is to prevent an accidental short circuit(a short circuit is often more dangerous to electronics than ESD), and to slow the static discharge to prevent EMP.
I usually use a ground strap connected to the case on my power supply.

 

[hank]

And reason number two? (Hint -- it's not to protect the electronics) ....

 

[Darell]

So that when you light up, you light up only dimly?

I'm bad. I throw all caution to the wind when playing with LEDs.

 

[snakebite]

to prevent a life threatening shock if you touch something live!

 

[luxO]

Originally posted by star882:
The resistor is to prevent an accidental short circuit(a short circuit is often more dangerous to electronics than ESD), and to slow the static discharge to prevent EMP.
I usually use a ground strap connected to the case on my power supply.

<font size="2" face="Verdana, Arial">No, the resistor is to protect the human, not the machine.

 

[**DONOTDELETE**]

Hank; Re: ESD
I'm no expert though I did work in an ISO electronics manufacturing plant for three yrs. (cert. thru whole/ surface mount)(worked with LEDs alot) and kind of wondered if the pics of mods. I see are eventually secured in protective housings. ESD awareness is greatly stressed. Wrist straps/ foot straps were checked daily to make sure they were functioning properly. All workstations were properly grounded and checked weekly.Components and circuitboards were always protected either in specially designed bins or static free component bags.I also wonder about the solder, flux, wicks, and cleaning solutions you folks are using. There are three kinds of solder(regular, no-clean, rosin) two kinds of flux.We were not allowed to use flux with rosin solder.Wicks and flux were matched according to solder used. Cleaning sol. are quite specific(ie no alcohol with regular flux). Applications are quite specific and so one should check with manufacturers' recommendations. Hope this helps...

 

[**DONOTDELETE**]

Re:Additional thoughts on ESD and flux.It has been demonstrated that static electricity can severely damage circuit boards.Flux can also seep into and contaminate boards.We used di-ionized water (to clean) for regular flux even though this flux is alcohol based; and for no-clean flux(which should be used sparingly)alcohol (on a Q-tip) is used.)....

 

[carbonsparky]

The white LED is not that sensitive as to require full blown ESD protection. If you can avoid carpeting, low humidity, and synthetic fiber clothing you can get away with almost nothing else for protection other than a wrist strap or a grounded grab rail. Keep these things away from you work space; poly bags ,styrofoam, or any other material that likes to charge up. I store my white LEDs in anti-static foam and only remove them when installing them in place.

 

[hank]

I was wondering about ESD because I noticed Nichia's web page has very detailed instructions on handling their white LEDs, and testing them after assembly is completed as well, to catch those that were damaged (not completely killed, but degraded and made unreliable) by ESD.

 

[SureFreak]

I use a "customized" computer power cord to plug into the outlet and connect to the computer:
Here we go, I had to attach an image...plain text wouldn't display the diagram correctly

I removed the two flat prongs with a dremel (rep. by 'xxx'), but left a little bit sticking out to keep the plug in position, then I opened the tubing around the wires and cut about 6 inches from the positive wire and about 12 inches from the negative wire, wrapped everything back up, and TADAAAA!!! Just replace the power cord with this one and you can connect your wrist strap to the case and you don't need a anti-static mat...plus no worries about getting shocked. I can tell you it works, I've built two computers this way, and it is pretty comfy.

This will work if you are doing your led work near your computer.. If you aren't, just cut the plug that goes into the back of the computer off, remove as much of the + and - wires as possible, and use an alligator clip to connect to the ground wire.
***NOTE*** If you use either of these methods, be sure that your wrist strap has a resistor on it...power "backwash" can be pretty painful [so I'm told(?)]

Regards,
Steve

 

[SureFreak]

btw another good way to protect leds is to always put them on one of those orangish-pink non-conductive bags that come with cd and dvd drives.