Static Electricity and ESD Protection for Electronics

I want to tell you - how static electricity forms and then explore how to avoid it in life and industrial properties.

The formation of static charges is influenced by wind creating friction on surfaces, thunderstorms ionizing the air, and operating equipment through induction.

Humans also contribute to the generation of static charges. During movement, a person generates a significant amount of static electricity up to 15 kilovolts. Humans are like capacitors, accumulating charges, especially when wearing non-conductive footwear.

These are the most fundamental factors behind static electricity.

Static charges are distributed unevenly on surfaces. It is impossible to say that the space is equally electrified or charged. The places of charge accumulation are in different spots and the charge level is different. On the walls - there is a charge here, there is no charge there.

The closer to the grounding buses and the earth, the lower the level of electrification, because it is easier for charges to drain with less resistance of air and surfaces. Including through any metal surfaces that are connected to the earth somewhere.

Wind and thunderstorms must be taken into account and therefore it is necessary to be initially prepared for the fact that these natural phenomena will generate static in any case. And it is possible to work with the generation of static electricity by people and equipment.

Ways to protect against static electricity:

In various industries, including electronics manufacturing, it is necessary to work with static voltage using grounding. And also using various devices and air humidification.

Working with static charges and ESD Protection is very important because static can cause fires, sparks, and electric shock.

First, all equipment must be grounded. The building and room’s grounding system should be verified.

Second, the air humidity must be maintained.

For critical processes, like electronics assembly, air humidity plays a key role. Humid air increases conductivity, allowing static charges to dissipate into the ground, reducing static spots on surfaces. Humidity should not fall below 50%. Workers entering such facilities should pass through special devices that discharge them. You stand on designated platforms, touch a plate with your finger, and the device gently discharges the static from your body, ensuring no charges remain.

If a charged person enters a production area, their charge can transfer to equipment and PCBs, potentially damaging it. Conversely, static from ungrounded equipment can transfer to the person.

What if a charged person touches microchips without ESD protection or circuit boards on a grounded table? There’s a high chance of damaging those components. A spark will fly from the finger through the chip or PCB and out onto the grounded table.

Equipment and workers in fixed locations must be grounded, and air humidity should be no lower than 50%. Workers handling equipment must use ESD wrist straps connected to ESD outlet with 1 megaohm resistance, which are connected to the building’s grounding system. This ensures the worker’s potential is equalized to nearly zero volts. Grounded equipment should also be directly connected to the grounding system.

This setup eliminates static charges from both people and equipment, preventing sparking.

At home, the situation is somewhat similar, but many household devices are not grounded.

Many homes worldwide don’t have three-wire grounding systems. In my home in Florida this question does not arise.

At home, static electricity can be managed using a humidifier. Increasing air humidity reduces static buildup on surfaces and on you. You can measure humidity with a hygrometer. In a room with normal humidity, static charges on you and your equipment will be able to dissipate naturally through the air into the ground. This also prevents sparks when you touch house appliances like refrigerator or oven. However, this solution applies indoors. Indoor air humidification is one of the key factors that can remove static electricity from surfaces and from a person. Of course, the grounding should be working in all outlets and light switches.

Outdoors, such as when you approach your car in winter and feel a shock, the issue is due to potential equalization. For example, if your body has a potential of 3,000 volts and the car has 5,000 volts, touching it equalizes these potentials. Note that neither you nor the car is fully discharged to zero—only the difference in potential is equalized.

If you walk barefoot in the snow and there is zero volts on you, and 5000 volts on the car, then the potential will equalize to zero! Can you imagine what kind of discharge will flow through you?! The car is on rubber wheels and the static discharge from it flows very poorly into the ground.

The car is insulated from the ground and in this case an antistatic belt will help, which is attached to the metal of the car, and the belt touches the ground from below, allowing the accumulated charges to flow from the car into the ground.

In the case of a car, the only way to protect yourself is to wear gloves to prevent the charges from flowing. The gloves will be an insulator.

You can't get away from this phenomenon.

I also want to talk about liquids that are applied to surfaces indoors. Many believe that these sprays should prevent the accumulation of static charges on the surface.

I admit that static will not accumulate in the place where you applied the liquid. But it will definitely accumulate around. If there is static electricity generation in the room, the charges will accumulate somewhere in any case. You won't apply these liquids to everything. I think its shelf life is not that long.

I don't know how harmful constant static electricity on our bodies, but many peoples say - walking barefoot on the ground is beneficial and feels refreshing. Perhaps this is because static dissipates, making us feel more comfortable.

Thank you for reading!