Many of the CMOS technology components used in your facility can be damaged by charges of less than 1, volts. Some of the more sophisticated components can be damaged by charges as low as 10 volts. You should be aware of the relative sensitivity to ESD damage of devices you may be working with. As electronic technology advances, electronic components tend to become smaller and smaller. As the size of the components is reduced, so is the microscopic spacing of insulators and circuits within them, increasing their sensitivity to ESD.
As you can predict, the need of proper ESD protection increases every day. Static damage to components can take the form of upset failures or catastrophic failures. This is the easiest type of ESD damage to find since it usually can be detected during testing. Latent failures occur when ESD weakens or wounds the component to the point where it will still function properly during testing, but over time the wounded component will cause poor system performance and eventually complete system failure.
Because latent failures occur after final inspection or in the hands of your customer, the cost of repair is very high. An upset failure occurs when an electrostatic discharge has caused a current flow that is not significant enough to cause total failure, but in use may intermittently result in gate leakage causing loss of software or incorrect storage of information.
In other words, static damage may occur that cannot be felt, seen, or detected through normal testing procedures. Damage caused by invisible and undetectable events can be understood by comparing ESD damage to medical contamination of the human body by viruses or bacteria. Although viruses and bacteria are invisible, they can cause severe damage even before you can detect their presence.
A defense against this invisible threat is sterilization. Peak currents don't differ greatly, ranging from 19 to 29A , as electrodes are changed from sharp Fig. Peak currents at this 4 kV level range to 23A. So if discharges from a finger are an order of magnitude lower, we can guess that they peak around 3 A. You can see that these peak currents only last a few nanoseconds, though.
The amount of voltage generated by the static shock varies on the method used to obtain the static shock and the materials used. This post is an interesting look at the situation. The resistance of a human is very hard to quantify and varies depending on conditions such as moisture, gender , body type, body part, path the voltage takes, and what they're wearing.
We can practically consider a person's total resistance as the resistance of the skin going in, the internal resistance and the resistance of the skin going out in in series going, the total resistance is the sum of all the resistance. Mcgrew who came into direct contact with a transmission line. But I believe that it is only when there is a sustained current, though I can't find how long it needs to be sustained on average I suppose they don't ever test it because we don't want people to die.
Also keep in mind that this is applied for a tiny amount of time, likely a fraction of a tenth of a second. The real value may be somewhere between these two, but I bet it's more towards the second than the first.
To get a spark in air under standard conditions you need a potential of approximately 3kV per millimeter of distance. If you see a spark just before your finger touches a doorknob, you can use that to roughly estimate what the voltage difference was. Electric charge flows very briefly between your finger and the doorknob, until the potential difference between them is no longer enough to overcome the resistance. For electricity to be lethal, you need the current to flow through a vital organ, like your heart.
The datasheet for a human being is probably pretty long: humanoids have complex topology and different types of tissue have different resistances. Dry skin has a much higher resistance than many of the wetter squishy bits on the inside.
If you where to reach out to two different doorknobs that had a large potential different between them, then your body would be a conductor with moderate resistance. Given that your skin has pretty high resistance, the current would likely flow along the outer layers for your skin. But if the current persisted for more than a split second, your body might dump moisture out your sweat glands. That moisture drops the skin's resistance, making the route through your insides much more attractive.
People who work with high voltage are taught among other things to where rubber soled shoes and to work with only one hand. The idea is to reduce the chance of completing a circuit with a large portion of your body. If you accidentally "short" a circuit with your hand, you might get a nasty current running through your fingers and hand see Electroboom's YouTube channel for examples , but that's better than having it flow through the trunk of your body where the life support systems are located.
Electrodes on Taser are arranged to send current through a short span rather than across the core. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group.
Create a free Team What is Teams? Learn more. For example, polishing a glass plate with a silk scarf electrifies the scarf so that it acts like a magnet. At even more disparate ends of a series, the friction of rabbit's fur on a Teflon pan generates additional electricity.
When you stride across a wool carpet in leather shoes, your shoes pick up extra electrons from the carpet with each step. By the time you lift your foot up off the ground, the electrons will have spread around your entire body, giving you a negative charge. The next time you put your foot on the carpet, your shoe doesn't have any extra electrons, but your head might.
So more electrons make the leap to your foot. You end up with a high voltage, about 20, to 25, volts. That's serious power at your fingertips, considering a normal electrical outlet on the wall is only around volts of electricity. Electrons are like fickle friends. Even though they were attracted to you in the first place, they don't like to hang around for long and they're always looking for a way out. From the impact of your voltage, the air between your hand and the knob grows extremely hot and instantly turns to plasma , a fourth state of matter that differs from solids, liquids, or gases.
The plasma gives off a bright flash. The electrifying light show works just like a lightning bolt.
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