Question: Why do I only get a static shock when I touch metal?

Answer: Shocks are usually only felt if your body is charged to over about 4000V, and you touch something conductive (like metals or water, or other people).

If the wall or door is made of wood, concrete or some other material that has low or intermediate conductivity, any static charge on your body escapes slowly and usually does not cause a shock. If you touch metal, water, or another person when your body is highly charged, the charge is discharged quickly as the material is highly conductive. In this case you may feel a shock.

Every Thursday, Transforming Technologies will answer questions concerning all things ESD: static causes, threats,  ESD prevention, best practices and all things static in a feature we call ESD Q&A.  If you have ESD questions that you would like to be answered, email info@transforming-technologies.com  with Q&A in the subject line.

Question:  Does the weather affect static electricity?

Answer: You’ll often find dry weather will affect static electricity.

Shocks are worst under certain weather conditions. Static shocks will increase during the winter when the air outside is cold and dry. They may disappear in warmer damper weather.

Static charge build-up is enhanced when the weather is dry so static problems are often noticed more in dry air of the winter. The air outside can be very dry when the weather is cold. Indoors, central heating or air conditioning can give very dry conditions which promote static electricity. Heating warms the air and reduces its humidity.

Static shocks are often noticed in cold dry weather, especially when in a centrally heated environment, and may disappear when the weather gets more humid. Static shocks may also be encouraged under air conditioning in hot weather.  Many people choose to use a humidifier to increase air moister which helps dissipate static charges.

When there are ESD concerns in environments such as semiconductor or electronics manufacturing, the ANSI20.20 requires that temperature and humidity readings are taken when measuring static.  Typically a static field meter or a surface resistance meter are use to measure static and many take these readings as well as measuring static.

Every Thursday, Transforming Technologies will answer questions concerning all things ESD: static causes, threats,  ESD prevention, best practices and all things static in a feature we call ESD Q&A.  If you have ESD questions that you would like to be answered, email info@transforming-technologies.com  with Q&A in the subject line.

Question:  Are static shocks a health risk?

Answer: Static shocks can be a nuisance – but are not generally a health risk.

Fortunately there is little risk attached to such electrostatic discharges. In most cases they are just a common nuisance. The biggest risk is that a shock could cause you to have an accidental injury. For example, you might withdraw your arm suddenly and hit it against something.

Household static shocks, for example, are very high frequency and have a very short duration. According to LiveScience.com, it’s possible to generate up to 25,000 volts by dragging your feet across a carpet, though  the voltage of a typical carpet shock between a few hundred to a few thousand volts. People can typically feel static at 2000 volts. Either way, household static shocks are almost always harmless. Most of the shocks that electrocute people are at a much lower frequency, a much longer duration, and have more energy creating a much more significant driving force.

Every Thursday, Transforming Technologies will answer questions concerning all things ESD: static causes, threats,  ESD prevention, best practices and all things static in a feature we call ESD Q&A.  If you have ESD questions that you would like to be answered, email info@transforming-technologies.com  with Q&A in the subject line.

 Question: Why do I get static shocks when I touch the door knob?

Answer: Static charges build up on shoes when you walk.

Most modern shoes have highly insulating rubber or plastic soles. As you walk, static charges can build up on the soles of the shoes. This is especially true if the floor is also insulating. Some older nylon carpets are particularly good at generating static electricity.  The charge on the shoes soles induces static electrical charge on your body, and when you touch something conductive, such as metal, the static will discharge and cause a the shock. If you are indoors, the point can be proved by walking around for a while with no shoes on – you will probably not experience shock.

Every Thursday, Transforming Technologies will answer questions concerning all things ESD: static causes, threats,  ESD prevention, best practices and all things static in a feature we call ESD Q&A.  If you have ESD questions that you would like to be answered, email info@transforming-technologies.com  with Q&A in the subject line.

Q:  What is “ESD”?

A: ESD is short Electrostatic Discharge.

Electrostatic Discharge, or ESD, is a single-event, rapid transfer of electrostatic charge between two objects, usually resulting when two objects at different potentials come into direct contact with each other.  ESD can also occur when a high electrostatic field develops between two objects in close proximity.  ESD is one of the major causes of device failures in the semiconductor industry.

Electrostatic charge build-up occurs as a result of an imbalance of electrons on the surface of a material.  Such a charge build-up develops an electric field that has measurable effects on other objects at a distance.  The process of electron transfer as a result of two objects coming into contact with each other and then separating is known as ‘triboelectric charging’.

This charging process results in one object gaining electrons on its surface, and therefore becoming negatively charged, and another object losing electrons from its surface, and therefore becoming positively charged. A person can get triboelectrically charged in a number of ways, even by just walking across a room.

Every Thursday, Transforming Technologies will answer questions concerning all things ESD: static causes, threats,  ESD prevention, best practices and all things static in a feature we call ESD Q&A.  If you have ESD questions that you would like to be answered, email info@transforming-technologies.com  with Q&A in the subject line.

Q:  What is the greatest static threat to electronics and other materials?

A:  YOU!

The human body can generate the biggest charge of anything likely to come near these devices.

Charge can often build-up on people and reach levels that give uncomfortable shocks, can damage sensitive electronic parts or give fire risks when handling solvents and other flammable materials. Dry air humidity encourages static charge build-up, and under dry external conditions the atmosphere in a building can become even drier. Electrostatic charge build-up can be far worse under these conditions. For example, on a dry day, humans can generate a static field of more than 100 volts by just the slight raising of an arm.  During normal, everyday activities, it is common to generate 6,000 volts or more.

Every Thursday, Transforming Technologies will answer questions concerning all things ESD: static causes, threats,  ESD prevention, best practices and all things static in a feature we call ESD Q&A.  If you have ESD questions that you would like to be answered, email info@transforming-technologies.com  with Q&A in the subject line.

Q:  When does Static Damage occur?

A:  ESD damage can occur to devices at anytime – even after they have been installed on circuit cards.

Damage can occur simply by placing a fingertip too close to a component inside an open computer!  Everyone involved in the handling, installing, test, shipping and storing of electronic devices must take preventative measures against the threat of ESD. Grounding yourself with ESD wrist straps or ESD heel grounders is the first defense against static damage.

ESD damage can cause immediate or “catastrophic” failure of component, or could gradually degrade components and cause a “latent failure”.  Latent failures are much harder to detect and can pass quality control tests in a factory. This maybe why your computer needs to have a motherboard replaced a year after purchase!

Starting Thursday, Transforming Technologies will answer questions concerning all things ESD: static causes, threats,  ESD prevention, best practices and all things static in a feature we call ESD Q&A.  If you have ESD questions that you would like to be answered, email info@transforming-technologies.com  with Q&A in the subject line.