Static electricity

[Fast Pistoleros]

hello,

I am experiencing an unusual amount of static in my house this winter..not sure why, maybe I am noticing it more since I am into electronics or if it is more prevalent this year.  I am afraid to touch any of my expensive parts lol.

might be time to invest in a bracelet or a bench mat. What do you guys think ?

[R.G.]

Static electricity can only happen when you have both low humidity and insulating surfaces. One really good way to avoid the issue is to raise the humidity. In a pinch, you can go into your bathroom and run a nice, hot shower for a while. That steam makes the air in the bathroom wet, and you can work in there with no problems with static. It can't form there until the air dries out.

Another useful tip is to take off your shoes and socks and wear cotton clothes. Cotton doesn't insulate like synthetics do, so it is much less likely to form static charges. Bare feet bleed off charge in a way that dry shoe soles can never do.

I would try those before going all "approved static free workstation". In several decades, I've never worn a wrist strap, and never killed a chip by static - but I did work barefoot a lot.   

[armdnrdy]

The humidifier that's stored deep in the closet or up in the rafters would suffice for a small to medium size room.

[Kipper4]

Yep I had a similar issue once or twice since I bought new trainers. (Sketchers memory foam soles)
Defo try the shoes thing.

[amptramp]

You can get safety shoes with a high resistance path to ground and wear an ankle strap as is done in a number of manufacturing environments.  These are sold as anti-static shoes.  I do not recommend soldering in bare feet.

[bluebunny]

In a pinch, you can go into your bathroom and run a nice, hot shower for a while.

Paul's usual advice is to cook a large pan of pasta.  Just in case you prefer working in the kitchen rather than the bathroom.   

[Jdansti]

^ Or move to Houston, Texas. No lack of water vapor here!

[R.G.]

^ Or move to Houston, Texas. No lack of water vapor here!

I think that actually moving to Houston is overkill. Houston is widely viewed as uninhabitable by humans on grounds of the amount of humidity. 

[bluebunny]

^ Or move to Houston, Texas. No lack of water vapor here!

I remember it well: emerging from the airconned airport into the hot gloop of the Houston "atmosphere".

[Fast Pistoleros]

you dont humid until you experience august in st louis ..most likely just pollution though lol

[bloxstompboxes]

Humidity in Kentucky stays in the 80 -90% range most of the hot months of the summer. You go outside and instantly feel sticky.

[Fast Pistoleros]

my first day in digital 200 was this morning. which is the lowest level class you can take, professor told us its only CMOS you need to worry about and that its not that big a deal he said ..nothing to really worry about.  This class is insanely tough already. first lab we had an IC counting in binary code ..learning to speak in digital lol ..oh my its going to be a rough semester lol

I wanted to make sure since I am buying some transistors which cost 10-20 bucks a set or a per unit in some cases and do not want to ruin them in any way .

[PRR]

> actually moving to Houston is overkill.

Indeed.

Though here in the coastal woods of Maine, 30+ days each summer without A/C we would have 99.9% RH in the house. Stair hand-rails damp in the morning. ("Spanish Moss" grows on our trees, it can be that steady-damp.)

30 days is not 360 days, I grant.

OTOH it is 29% RH inside today (burning the gas to defrost my fingers). Somehow the static is not *too* bad; I think there's more damp coming out of the wood and walls yet.

> I am afraid to touch any of my expensive parts lol.

Resistors, caps, diodes, BJTs, JFETs, and most chips are not likely to fail because of body static. Fondle them all you want. (Someone will say that some sensitive BJTs can be degraded by static; true, but not usually so you would notice in small-audio work.)

MOSFETs and CMOS are traditional exceptions.

When these were new, winter failures abounded. A memo went out "We must carefully watch our workers' undergarments." Turned out it was easier to develop more robust static protection in the devices than to question the workers' choice of undergarments. I would expect any CMOS/MOSFET made in the last few decades to be "static proof" in most dry environments. i.e. dry so you get minor shocks on doorknobs, not arm-numbing shocks.

If you wear silk/nylon stockings and slips, you know "static cling", and you probably have a spray you use on dry-cling clothing.

Cotton is better. Not that cotton is anti-static itself, but it holds moisture in its pores and that bleeds-off the static charge about as fast as it charges-up. Silk, nylon, etc don't have moisture-holding pores.

We can't replace nylon or poly carpets. What you do is get liquid Fabric Softener. What this really is, is a moisture absorber, keeps fabric from going dead-dry. Use it in your wash; all-cotton is rare now and your jeans have plenty of poly fiber. They need help. Also put a spoon full in a quart spray bottle of water. Mist it on your carpet, couch, throw-blankets, and around your work-space every time you start to feel shocks. The original IBM PC keyboards used to lock-up when a worker walked across the carpet and put a finger near the keyboard; my job was to spray office carpets several times each winter. I shoved that job but still do it around the house. We have a couch-blanket which almost makes lightning-strokes when thrown off quickly.

And yeah. shower and pasta so there's some damp in the air for the fabric softener to absorb.

The really big danger is when your charged-up body touches one leg of a part, and you put another leg of the part in a large conductive object (PCB). A wise precaution is to touch all the big then medium stuff, frequently, before and while you touch small stuff. When I opened a PC to add RAM (cheap RAM could have cheap static protection), I'd touch the power supply box (large bare metal wired to everything else) before opening the RAM, and again just before I stuffed it in the socket.

[greaser_au]

Most organisations take (and are often required to take- by contract) the safe road and treat everything as static-sensitive. I recall the training films with 1k metalfilm resistors with holes blown in the resistive elements...   I think Vishay have some ESD informational videos on the 'web.

david