I'm currently reading the 6502 primer and on the part where it says "work on an antistatic mat and wear an antistatic wrist-band", I told myself "welp, never did that"
How do you know you made damage to your components? Do they simply stop working? Or do they behave unexpectedly?
As a beginner, I'd rather have it not working at all than making things it's not supposed to be, cause I don't know the IC normal behavior yet.
If you live on nylon carpets, in a dry climate, and scuff your feet, you might have a problem. If you often get shocks when you touch metal, you might have a problem. But a lot of people take no care and have no problem.
So, like a lot of advice, this advice is about reducing risk. Sometimes you can cross the road without looking. (Don't make a habit of it.)
You will almost certainly have to debug your constructions in any case, so I'd say go ahead.
(But also: everyone has a different risk profile, and different resources. If you'd be happier rebuying everything and starting over, go ahead with that plan!)
Do they simply stop working? Or do they behave unexpectedly?
Unfortunately, a lot of different symptoms are possible, so you can't necessarily predict what will happen. But I can tell you two symptoms that are quite common. They will cover many of the cases that may arise.
Sometimes static or other damage will cause an input to get "stuck" high or low. The chip will behave according to the "stuck" value, rather than the correct value which is being applied by whatever chip is driving that input. ( Indeed, it may appear as if that other chip is defective. That's because its output may be unable to drive the other guy's stuck input, which means the driving chip's output won't be correct. )
A more easily detected symptom is when the damaged chip draws greatly increased current from the 5V (or 3V) power supply. The supply voltage may drop below its normal value, or the chip may become hot (perhaps VERY hot ) to the touch, or both.
BTW, static most easily accumulates in dry conditions (commonly experienced indoors in winter), so a humidifier is a useful form of protection. But get one that evaporates at least a liter of water per day -- preferably more. ( There are lots of ineffective, so-called humidifiers and vaporizers on the market. But if they don't require a LOT of water then you know they're not doing much. )
Pfeww seems I'm safe then I didn't notice any effet that you said and it's pretty moist where I live and I have laminate at home.
Never had electric shocks while working either.
I'm currently reading the 6502 primer and on the part where it says "work on an antistatic mat and wear an antistatic wrist-band", I told myself "welp, never did that"
Which page is that on? I don't remember writing that, and in fact under the heading "Static-Handling Precautions" of the logic-families page of the primer, you'll see that I say I myself don't use a wrist strap, and I tell basic methods that will keep the parts safe without going to great lengths. I am always mindful of it, and have personally never damaged anything with static, as far as I can remember. At a place I worked in the mid-1980's, they required the production people to use the finger cots, booties, smocks, wrist straps, etc., and they still had quite a percentage of the parts fail, because some production girl would pick up a tray of parts to carry it to the next station, and the leads would be touching the metal tray, and she didn't think she needed to be grounded because she wasn't touching the leads directly, just the metal tray which had a 0Ω contact to the leads. These were VHF and UHF power MOSFETs whose flat leads made them look like little satellites with solar panels sticking out from the sides.
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How do you know you made damage to your components? Do they simply stop working? Or do they behave unexpectedly?
I think they will mostly show signs of an input not working and being shorted to a rail or something else, definitely not being high-impedance anymore.
I have been extremely careless with most of my stuff and have never caused any static damage. In my wide but shallow range of experience you are much much much more likely to hook something up wrong and damage a chip than to damage something from ESD. I melted 3 555 timers into a breadboard (the first was an accident, the other 2 were for my own amusement) by hooking them up wrong. A more recent case was not paying attention to how I put a 74hc595 into a circuit (had it in backwards) and then burning my finger on it when I went to remove it. If you are working with tiny surface mount IC's (particularly jfets or mosfets) it might be worth getting a wrist strap but generally speaking incorrect connections are much more trouble.
EDIT: also, I remember reading that part on your page recently Garth. It's there, if I remember to check for it I'll see if I can get a location lol
If you are working with tiny surface mount IC's (particularly jfets or mosfets) it might be worth getting a wrist strap but generally speaking incorrect connections are much more trouble.
Don't worry about the JFETs. They don't have the gate insulation to puncture like the MOSFETs do. They're a lot like bipolar transistors, just arranged differently.
in fact under the heading "Static-Handling Precautions" of the logic-families page of the primer, you'll see that I say I myself don't use a wrist strap
Oops I might have added that thing about the wrist strap in my head seeing the "getting away with an antistatic mat" portion triggered in my mind "oh I need antistatic protection, including wrist strap"
But yeah this was this exact section I was referring to.
Oh and btw this primer is gold I might have to read it a few times cause there's a lot of information but wanted to thank you for that
I get zapped all day every day with static in my home. Thankfully never fried anything yet. Since getting back in to electronics over the past year, I have been lazy and just stick my hand on the computer tower to discharge myself. I only recently purchased an anti-static wrist band, now that I am playing with CPU's and RAM more often. I don't want to start frying the more sensitive chips.
But static being what it is, it's hard to say how a chip may malfunction, especially a CPU. RAM would likely be easier to diagnose, with bits stuck either 1 or 0 (or not working at all).
Personally, as I don't have much nylon and the carpets are ok, don't get shocks, etc, I just touch unpainted metal earthed points once in a while. I used to be much more concious of potential static damage as, many years ago when I were a young 'un, I used to work as an ATE operator (considered the lowest of the low) for a company which would put inductees through the worst kind of "training" : a VHS tape being played on an old style CRT in a dark room with the heating turned up. You had to go in with a box of match sticks to keep your eyes open.
One of said training videos was about static damage and antistatic precautions and they had some very interesting close ups of ICs showing big holes (well, big if you zoom far in enough ) blown through the silicon and it went on to say that even that kind of severe damage might not be totally fatal, but can vastly reduce the life span of the IC in question or give erratic behaviour. Given that some of the PCBs we handled were for very expensive (military, in some cases) systems, management were keen that we didn't blow stuff up. If you didn't wear your antistatic foot straps, antistatic coat, etc. then woe betide you .
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As someone who has fried several things with static electricity, both accidentally and on purpose, I have a bit of experience in this department. I also do failure analysis as part of my engineering work and have seen several devices from the field with ESD damage.
Several of the symptoms I've seen myself have already been listed, but they are worth repeating. I'll give them in the order of how often I see them. Some of the items later in the list are more specific symptoms of something from the top of the list that doesn't always happen.
1. On MOSFETs, the gate is no longer isolated from the source/drain. This can cause damage to whatever is driving the gate as it might be shorted (or partially shorted) to power or ground. MOSFETs are commonly used to control load with higher voltage supplies, and that higher voltage might get into the micro section of the circuit and fry the micro as well.
2. Device is dead. There might be a very small tell-tale circle of melted plastic on the top of the IC somewhere over the die where a tiny puff of magic smoke escaped (this is actually secondary damage caused by localized heating at the point of the ESD damage).
3. Device works, but draws more power than it should. It runs hotter than normal. Sometimes this is only a small amount of extra current (eg. 1mA more than normal on a 20mA circuit - you'd only notice with a multimeter) and the temperature rise is undetectable with a finger. Other times, you will burn your finger on the IC, but the circuit will still be functioning. Sometimes the damage starts as the tiny leak and the leakage increases over time (anywhere from hours to months) to become the burn-your-finger type damage before the circuit finally stops working. That's the type of damage that manufacturers are worried about (latent esd damage - where it will fail at a later date) because a device might pass all the regular tests the manufacturer uses before shipping the product, but it might fail days/weeks/months later.
4. Damaged MLCC (Multi-Layer Ceramic Capacitors). These are the little surface-mount capacitors (often tan with no markings on them) you see all over surface-mount PCBs. These might have 50 layers in an 0603 size (that's 0.06"x0.03") capacitor, so the layers are very close together. ESD can cause "punch-through" that damages the super-thin layer of ceramic between the conductive layers and can cause them to short.
Because these caps are often used to bypass power to ground, that short can cause the cap to get hot. If it's a weak short, the cap will just draw some extra power (like a resistor from power to ground would) but otherwise it might still partially function as a cap. If it's a medium short, it can cause localized heating between the layers that can actually crack the capacitor in half (the ceramic is very brittle). If it's a strong short, the fuse blows (you *DO* have a fuse in your circuit... right?).
5. An I/O pin is stuck high or low or has a very weak high (can't pull all the way up) or very weak low (can't pull all the way down). If the pin is an input, it might look like the chip driving the pin is having trouble when it's really the IC with a damaged input that's loading the line up/down. Dr. Jefyll mentioned this, and I've definitely been bit by that when debugging a circuit, so it's worth mentioning again.
Simple Mitigation Strategies for Non-ESD-Safe Environments:
0. Just be mindful - if you are constantly getting zapped throughout the day, or if you are working with components that are easy to damage (eg. MOSFETs when they are not in a circuit yet) then you might need some of the precautions below.
1. Avoid wearing wool or synthetic fiber clothing when working on electronics - these types of fibers can cause static charging when you move around (esp. when you sit down or get back up from a chair). Cotton does not have nearly as much tendency to do this. Certain shoes can also be problematic.
2. Humidifier - keep above 40% RH (Relative Humidity) if you can.
3. If a humidifier isn't possible, and you're zapping everything anytime you move around the room, use an anti-static spray to reduce static build-up. The commercial stuff smells terrible and doesn't last very long, so I make my own with fabric softener + water (I use about 1:4 mix - it's not critical) in a spray bottle which lasts for several hours and smells a lot nicer. Spray all of the surfaces that cause you to become charged (eg. chairs, floor, etc) before you start working on your electronics.
4. Locate a touch point to touch before working with ESD sensitive items. Most devices with a metal housing and a 3-prong plug should have their case tied to ground and can be used for this purpose if they have an unpainted surface (eg. an unpainted screw as long as it screws into metal). I have a small metal disc attached to the ground terminal of my bench power supply that I use. The touch point should be reachable (and used) immediately after sitting down at your workspace.
5. Don't hand electronic devices directly to another person because you are likely both charged to different voltages. Having an ESD go through a component is the best way to cause damage, and humans can develop/hold a pretty reasonable charge. Either set the device down on a non-conductive surface and let the other person pick it up, or touch them first with a finger to equalize the charge between you before you hand them the device (better to zap between fingers instead of through device). Once you both are the same charge, you can hand things back and forth, but you should redo this each time anyone sits down, stands up, or walks around.
6. Avoid setting or touching a sensitive component on a metal surface (in general, don't use metal surfaces with your electronics - you're just asking for trouble in a bunch of ways). This has the same problem as two people.
For hobby electronics, you don't need a a full ESD setup, and you probably only need to consider the above mitigation strategies if you're having a problem zapping everything in sight or you're working with something you know is very static sensitive.
This reminded me of something that has been bugging me ever since I bought it. I got one of those 'helping hands' thingies with the assorted magnetic arms and pegs. Its absolute garbage btw, the pegs are fine because they are just cylinders machined to a tip, hard to mess up, but the arms have weak magnets so they tip over fairly easy and the grippers literally fall out of the arm. But I use it as a base for soldering and sometimes find a use for the arms or pegs. The base is made of what appears to be just a steel plate with rubber feet and the soldering iron holder, the pegs, and the arms have magnets on them. This seems like a recipe for a vortex of possible issues. The metal base is painted but even with that said the whole setup seems like a bad idea?
) to the touch, or both.
seeing the "getting away with an antistatic mat" portion triggered in my mind "oh I need antistatic protection, including wrist strap"
I might have to read it a few times cause there's a lot of information but wanted to thank you for that
) blown through the silicon and it went on to say that even that kind of severe damage might not be totally fatal, but can vastly reduce the life span of the IC in question or give erratic behaviour. Given that some of the PCBs we handled were for very expensive (military, in some cases) systems, management were keen that we didn't blow stuff up. If you didn't wear your antistatic foot straps, antistatic coat, etc. then woe betide you 