So I just go an order of TL072's, PT2933's, and a few other semiconductors that I forget, and I just realized that I don't know how to handle them properly. :icon_frown: I did some searching and couldn't find much in the wiki or the Search on it, but maybe I just was not persistent enough.
The BS170' appear to be packaged ESD safe. The IC's are in some sort of pink foam that I can only assume is conductive. Before I'm tempted to start messing with this stuff, though, I want to make sure I'm not going to do something really noobish and destroy all my hard-earned loot. I have cats & carpet after all. :icon_evil:
Do I really need one of these wristband thingies? What is the proper way to use one? What precautions do you personally take when working with ESD sensitive components?
(http://media.digikey.com/photos/Desco%20Photos/09070.jpg)
+1 on this...
I also don't wanna cook this stuff after playing with the dog. Is the band needed?
Are you getting shocked when you touch the doorknob?
99% of the year, I handle TL072 CMOS etc just bare-hand. If in foam, hold the foam then grab the chip. Put the other hand on the PCB. Now stuff the chip and solder.
I never wear silk panties while working, just old cotton blends.
If the static is really bad, make spaghetti. Raise the humidity.
yeah man! if your putting this in an enclosure that you are going to be wailing on with your foot constantly it has to stand up to some brutality. If it is going to die from you touching it don't bother.
I believe PRR speaks truth...
I've handled all kinds of stuff and never had anything zap on me, but just to be on the safe side, sometimes I touch a bare metal part of my computer case after petting the cat, etc.
If you already have one of those strappy things, you could wear it just for your own peace of mind...
Quote from: PRR on December 17, 2010, 01:18:12 AM
I never wear silk panties while working..
Same here. I only wear silk panties while lounging.
:icon_biggrin:
If you have problems with static shocks around the house, a grounding wristband is a good idea. Otherwise I wouldn't bother.
I've posted this several times here, and in other forums.
To avoid static electricity damage:
1. Wear cotton. It's the high-triboelectric synthetics, silks and furs that are very static prone. So wear cotton clothes. This is the one place I know of where wearing jeans is a technically valid thing to do in electronics.
2. Take off your shoes and socks. Shoes tend to have soles which create static with synthetic carpets. Feet are not so bad.
3. Make the humidity higher. Static electricity bleeds off in air with humidity over about 35%. So if you have to ensure no static sparks, make the air wet. Work in your bathroom with the hot water spraying in the shower to make the air wet in that room.
The static-free pads, wrist bands, etc. work, but preventing it in the first place is simpler.
I save my silk panties for special occasions
personally, I never bother grounding myself. never have whilst working on any electronics, weather it be Pedals laptops, computers etc. Unless your prone to It, I woldn't worry.
Although I do have a question....
What about storage? I bought a tray based storage system for componets, will static build up inside said unit pose a problem for potentially sensitive components? I mean, the ICs live inside plastic ESD protective sheeths anyway mainly so pins dont get damaged, but I bought a bunch of 2n3906s and unlike any of my other transistors, they came in an antistatic bag. Do certain componets have higher risk assocoiated with ESD, or should I not worry and just negate the bag and throw it in its own compartment in the draw along with the other trannies?
J
Wow, a wealth of information after only a day. Thanks guys!
The weather currently poses a problem for going barefoot, though. Gramma made me some yarn slippers, but I don't know whether they are 100% cotton. :-*
I think I will make a conscious effort to apply Paul's advice and find out about those slippers.
Static electricity can easily achieve a PD (potential difference) of tens of thousands of volts, and it should be noted that every device has a 'breakdown voltage' somewhere. even resistors! Care needs to be taken concerning static with anything, but mainly MOS (4000 series ICs, MOSFETs, a lot of modern devices etc. etc.) because of the thin oxide layers used on the silicon die itself. It isn't the static electricity, but the movement of the charges that causes the problems.
I worked for several years in an electronics factory 20 years ago - there was a training lecture where they showed microscope pictures of metal film resistors with holes blown in the resistive film by static. EVERYTHING was treated as static-sensitive from a quality assurance perspective - that made sure there were no mistakes!! ALL parts were supplied in anti-static bags (even from the suppliers), storage containers were either conductive or treated with an anti-static 'wetting agent*'. Every workstation had static mats on the desk & the floor, everybody had their own wrist straps (or ankle straps if they needed to be mobile (e.g. machine soldering), the 'uniforms' had conductive threads through the fabric, and regular checks of the anti-static measures were undertaken, even checks of the ambient humidity levels.
I can hear the "I've never used static precautions and I've never had any problems...", and that is fair enough, but it isn't always failures- it's degradation of the components. I hear of noisy delay devices in these forums... That dodgy stick of ram in your PC... who knows... :)
From a practical perspective a grounded desktop static mat, a grounded wrist strap & a grounded soldering iron (most are these days) should be sufficient & cheap insurance. Always put on the wrist strap before picking anything up or sitting down. Storage containers (if they are obviously static-prone) can be dipped into a weak dish detergent solution (wetting agent*) & be allowed to dry.
Google "ESD procedures" for some interesting articles...
david
Air conditioning is your enemy, does the opposite to boiling a pot of spaghetti.
Otherwise, wear cotton, don't shuffle your feet across the carpet or the cat, touch an earthed appliance or conductive-but-isolated object (ie doorknob) before handling devices and intermittently while building. Simple precautions, and the probability of damaging a device will be quite low, and investing in ESD matting and banding will likely be an unnecessary expense, unless you are handling many hundreds of devices.
BTW, if anyone in the UK does want ESD protection, I can give you earth socket junction, wristbands, matting etc at cost price. I've probably got some stuff knocking around that you can have for free. Maybe send me your silk panties in return.
> touch a bare metal part
That's often the key detail.
Ponder the case of you, holding a chip, charged-up to thousands of volts, and approaching a more-groundy object.
Then you and the chip, but you touch the object before you put the chip in.
(http://i.imgur.com/jODMm.gif)
Poster #9 brings up another point I'm curious about:
QuoteWhat about storage?
Most of the posts so far have dealt with actually working with the components. I'm surprised that his BJT's were ESD packaged, I thought they were not very sensitive. Maybe they shipped from some place really dry.
I was thinking about buying Small Bear's op amp assortment, but the picture does not look like they are ESD protected. wouldn't that plastic tray pose some potential problems?
Quote from: BadIdeas on December 22, 2010, 06:21:53 PM
Poster #9 brings up another point I'm curious about:
QuoteWhat about storage?
Most of the posts so far have dealt with actually working with the components. I'm surprised that his BJT's were ESD packaged, I thought they were not very sensitive. Maybe they shipped from some place really dry.
I was thinking about buying Small Bear's op amp assortment, but the picture does not look like they are ESD protected. wouldn't that plastic tray pose some potential problems?
ESD protection is not that big a deal when we as a diy crowd deal with usually fairly resilient components and in small numbers. I have never killed a chip by handling it so far. I have an anti-static mat and wrist band, but I rarely use the unless working with chips that I feel might pose problems or with very sensitive electronics.
Just touch the leads as little as possible (you don't have to be TOO sensitive about it though, don't be using tweezers to pick up every part and giving yourself headaches while doing so....) and you will be fine.
For storage, I would recommend getting a few sheets of anti-static foam (if you plan on amassing a collection of parts). Line the bottom of whatever drawers or w/e you store parts in with this foam, cut to size, and stick all your IC's in it. It protects it from ESD plus lets you organize them very nicely & firmly.
The main worries about ESD are from factories whose workers handle thousands of chips a day and they want to minimize the percentage of defects in the product. Or from suppliers (like mouser) who don't want to have to replace people's orders because of unacceptable dead chips.
I've never killed an op amp or CMOS chip, but I've killed a couple microcontrollers from improper handling.
It hasn't happened in a long time since I now avoid touching the pins and place them in sockets with insulated tweezers.
Also, I work on a wood bench (no more cloth on it) and the shop has a concrete floor.
Great. Thanks, guys. You have put my mind at ease.
Anybody who has worked in a lab in the high tech field has probably had to deal with ESD training and using the wristbands and stuff. It's not as big of a deal with the discrete analog stuff that we use, especially BJT based stuff, as the breakdown voltage is relatively high. When you're working with newer IC's that can't handle over 3.3V or 1.8V at ANY port, ESD becomes a lot more important though (some have minimal, if any ESD protection). I've never personally ruined a device this way but I've been in testing positions where I am literally the last person to touch a board before it is shipped off. This is the sort of setting where you don't want to be caught without your ESD band on because if the board worked before you touched it and not afterward, it's your responsibility.
A good example: I built a microamp on perf this morning in under an hour. I found any dual op amp that I had laying around, sitting in my junk bin, fired it up and tested the board right quick. Then I went in my electronics room, grabbed a few more dual op amps for comparison purposes, threw them in my pocket and drove up to the music store. I was hot-swapping the IC's while the guy tried a few different bass setups and he settled on the TL072 for the low noise and least amount of coloring. The point is we work with penny parts usually and I tend to treat cheaper IC's as such. On the other hand, a lot of the specialized INA's I use up at school for medical instrumentation cost anywhere from $5 to $30 per chip. This is where I start being a little more careful about how I handle everything, but even these parts have internal ESD protection and I've never actually fried one this way.
Hey, so I have a wrist strap, but I was wondering where I should attach the alligator clip? The only places with metal piping or anything of the sort would be really awkward to work in. If I was to plug in an amp and attach the clip to the metal chasis of it, would that work? Or could that make it worse? I'm just wondering because my workshop's set up pretty much perfectly in terms of organization, but static might be a problem (it's concrete floor in a basement, if that makes a difference).
Pretty much any modern appliance that has a metal chassis and a 3-prong plug will be grounded. So, yes you should be able to clip it to the chassis as long as it has a 3-prong plug. If you replace the alligator plug with a banana plug you can plug directly into the the ground plug on an AC outlet (the circular one).
Seriously though, you shouldn't need a wristband. Take a look at the posts above.
When we had our first baby a few years back, everything had to be sterile before it came anywhere near the baby. If we dropped a nuk on the floor, it had to boiled before it could go back in the baby's mouth. Fast forward a couple years - and add some parenting experience. For the second baby, the ten-second rule applies - if it hasn't been on the floor for more than 10 seconds, blow the dust off and stick it in the kid's mouth.
Same thing with ESD protection. Relax. My work area is also a basement with a concrete floor, and I've never had a single component destroyed or degraded. I never get a static discharge when touching anything. When I build things, I just grab components out of my plastic storage bins, and they always work fine. So spare yourself the grief and fussiness of using a wrist strap, and skip it. If you have OCD tendencies, focus them on your soldering technique, and wiring layout instead.
Quote from: waltk on February 19, 2011, 12:27:34 AM
When we had our first baby a few years back, everything had to be sterile before it came anywhere near the baby. If we dropped a nuk on the floor, it had to boiled before it could go back in the baby's mouth. Fast forward a couple years - and add some parenting experience. For the second baby, the ten-second rule applies - if it hasn't been on the floor for more than 10 seconds, blow the dust off and stick it in the kid's mouth.
Same thing with ESD protection. Relax. My work area is also a basement with a concrete floor, and I've never had a single component destroyed or degraded. I never get a static discharge when touching anything. When I build things, I just grab components out of my plastic storage bins, and they always work fine. So spare yourself the grief and fussiness of using a wrist strap, and skip it. If you have OCD tendencies, focus them on your soldering technique, and wiring layout instead.
Haha, okay, I'll take that advice. Dang cord for the wriststrap's only like 2' long anyways, would just get in the way.
Just to clarify something for the OP, the black foam is resistive and will discharge anything plugged into it. The pink foam does not generate any tribological charge on its own, but it does not discharge anything.
As mentioned by greaser_au, components do not necessarily fail immediately - they may degrade and cause no problems for a while but fail later. Breathe on the stuff to keep the humidity up.