# Tag Info

40

There are two types of anti-static bag: static-dissipative (pink, red, or occasionally black) and static-discharge (silver or grey). Static-dissipative bags are designed to remove any static build-up that gradually builds up during shipping by transferring the charge to ground (i.e. what-ever the bag is touching). However, they are not designed to handle ...

32

If you are installing a CPU in a motherboard, you don't really care about grounding - what you really want to do is to make sure that you, the CPU, and the motherboard (and any tools) are all at the same potential. If you have one of those grounding bracelets, you should connect its ground lead to the computer case or motherboard Ground - whether that is "...

28

Is static electricity really so dangerous? Yes. The conductive paths inside an IC are really small, so it doesn't take much energy through them to vaporize them.¹ There are millions of such paths inside the ICs of an Arduino, and it only takes damage to one of them to break the device. It is possible that you could get lucky and break some feature that you ...

27

You (and the some of the other answers) focus too much on the actual value of the resistance to ground; the fact is that the actual value is irrelevant regarding ESD. The ESD charge just needs a path. If that path is high-ohmic (few mega-ohms) it will only take slightly longer for the charge to find its way to ground. But it will still be a fraction of a ...

25

I measure 1VAC and 20mV DC between ground and my radiator. I would consider that negligible. Very likely there is a connection somewhere between your radiator and ground. It might be a long path though, for example: Radiator - pipes to central heating unit - cold water pipes (does your heater also provide warm tap water?) - cold water grounding connection. ...

24

Overview: A good wrist strap system has a large resistance between the skin contact and ground. Typically this is 1 MΩ, which is relatively large. This large resistance is there for your safety, in case an error somewhere connects you to a hazardous voltage. Even this high resistance is sufficient for protecting your devices from ESD. A typical multimeter ...

21

If your plug has a correctly wired earth pin, then you can use that to ground yourself. However before you do, it is worth noting that all reputable ESD wrist bands contain an embedded 1MOhm resistor. This is done primarily so that if you accidentally connect yourself to mains voltage (either through what you are handling, or through a wiring fault in the ...

20

The 1meg resistor is needed to safeguard the user from faults from other equipment connected to mains earth. Keep in mind that the wrist strap is a permanent connection to the electric system of the building. If another piece of equipment experiences a fault, there could be a big fault current through the mains earth wiring system. That means that, in ...

18

First, the mat (and the connection to mains earth!!) should have a resistance that is high enough to cause no (extra) harm to you when 'normal' Voltages (let's say up to mains level) are involved. Think Mega-Ohms, and preferably more than one resistor in series to counter single-point-failure issues. As for the open/closed loop part: think of your body as ...

16

It makes no difference where you connect the anti-static strap to your body. The reason is that your body is much lower resistance between any two points than the strap is. Also, most of the resistance between any two points on your skin is getting thru the skin at each point. You're just a bag of saltwater (electrically, anyway). The bag has a ...

11

In most cars, you are isolated from the chassis when you're driving: everything is plastic, leather or textile. When you get out of your car, friction can rip off charges from the electrically neutral environment (this is called tribocharging) such that the potential difference between you and the ground increases drastically. When you set foot on the ground,...

11

Electrically, it doesn't matter where it makes contact, with contact being the key word! I find however that it doesn't suit my workflow round either wrist or ankle. If worn on my wrist, the trailing wire interferes with stuff on my bench. If worn on my ankle, it's a long way down to attach and detach, and being out of sight, it's easy to be working for a ...

11

Even if I doesn't take such precaution, chips behave as expected. Is that normal? Yes, ESD is an unpredictable event, and you can't see it (most of the time, sometimes you can see damage on IC's). Sometimes it only damages a trace partially and it could take months or years for a chip to fail, sometimes the effect is immediate and the circuit ceases to ...

11

While it is risky, if done properly, can provide an ESD safe place to work. Since you live on the beach near LA, this may be of no importance. Humidity above 60% or so makes ESD protection somewhat redundant. I'd get a sheet of 3 or 6mm plywood for the top (full sheet, not pieces which will let the table show through). An overhang of 2-3 inches on all sides ...

11

No, it would not. There's no conductive path through the silicone mat, so all having a proper one underneath it does is create a weak capacitor to ground, which doesn't help you.

10

Here is an excerpt from chapter 7 of Note: copying images because PDF files are protected and text cannot be copied. BTW: here you will find the entire book freely: OP AMP APPLICATIONS.

10

No, it will be fine. Just take the inner ESD bag fully out of the outer bag before removing the motherboard. The ESD bag ensures that all parts of the motherboard are at the same voltage. Any static charges on the outer bag will be evenly distributed by the inner one.

9

Can static shocks occur from grounded and ungrounded metals? Yes. A large ungrounded object still has capacitance. If there is a higher density of electrons on you than on the object, the electrons on you will feel repulsion from the other electrons on you and want to jump to the object where they will have more room to spread out. (Same goes in reverse if ...

9

No. "Anti-static" tweezers serve a different purpose than a wrist strap. A wrist strap keeps your BODY from building up a charge which can damage a component. Antistatic tweezers provide a "controlled" way of equalizing the charge between your hand and the component. So that it doesn't "zap" the component. If you disconnect the wrist strap, it allows ...

9

There are several considerations for your wrist strap. A) Safety for you B) Safety for your fragile components and kit C) Process, use them correctly D) Grounded? A) Your safety Your wrist strap should include a large amount of current limiting before connecting to a real earth. In practice, this is a 1meg resistor in the strap, and/or where you clip it ...

9

Using the safety ground on a three prong outlet is a valid way to ground yourself for ESD purposes. Many lab benches I have used have the ESD mat grounds attached to the ground that comes from a power cord feeding the benches. You can also buy an ESD grounding plug for a wrist strap that plugs into the ground on an outlet. Here is one example. https://www....

7

Get yourself one of these guys, and wire your ground into it. For good measure, double insulate the hot and neutral lugs inside the plug. The worst the kids will be able to do is unplug it, and they're less than \$10 at most places electrical products are sold.

7

A decent quality rubber antistatic mat will have a low end top surface conductivity of $10M \Omega$. Working with an audio circuit where the highest impedance is a $100k\Omega$? You'll never have a problem. Working with a $10M\Omega$ pH sensor? Leakage will cause you problems. This is a question that needs to be answered on a project by project basis,...

7

ESD is based on the fact objects can hold a static charge, e.g. when electrons are scraped off them by friction; contact with another object creates a destructive transfer of charge if not properly controlled. If rearranging your pullover can set a car's tank on fire, you can be sure ESDs can be dangerous to the incredibly tiny traces in any integrated ...

7

You have two questions which you think are related since they both concern ground connections. However the questions are not related ! Q1) The actual ground connection, where the return current from the supply flows, are the black wires on the ATX power connector. Indeed the chassis is also connected to the motherboard via the screws but this connection is ...

7

If by plan B you mean to add a resistor to the mains ground, then no plan B is not an option. If you add a resistor in series you will have two problems: 1) It affects the saftey of the earth mains, if you size the resistor wrong in the event of a fault you could have an issue with the resistor blowing out or creating common mode voltage in the case 2)...

7

You should NOT connect your anti-static gears to USB ground pin. The USB ground is SIGNAL GROUND. An ESD event can surge along the signal ground and elevate its potential relative to other ICs inputs (called sometimes as "ground bounce"), and it can damage internal ICs. If you don't have Earth ground on your workspace, at most you should use SHIELD of the ...

6

You are right. If you wear gloves, they should be sufficiently conductive so that their surface does not retain a charge, which gets discharged through you to your connection to ground. The purpose of all ESD precautions is to get everything at the same potential. It doesn't have to be 'ground', but that is the most convenient level to choose. So insulators ...

6

What is special about these screwdrivers that makes them ESD safe compared to other screwdrivers? The data sheet for that T4741SESD screwdriver set explains that: The handles are [...] electrostatically dissipative to DIN EN 61340 5,1 & 5,2 That is the difference. Therefore if you working at an ESD workstation, wearing an earthed wriststrap ...

5

Let's say I connect myself to the mat using an anti static wrist strap, how is it supposed to help me discharge my static charge when there is no closed loop between me, the mat, and the ground? As Wouter says, your body can behave like a capacitor, storing electric charge. A good example of a body storing charge is in the winter, removing a sweater or ...

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