Eight Ways Static Electricity is Generated
Static electricity is characterized by high voltage, low current, and short duration. Component breakdown damage caused by electrostatic discharge is the most common and serious electrostatic hazard in the electronics industry, and it is divided into hard breakdown and soft breakdown. Hard breakdown causes dielectric breakdown, burnout, or permanent failure of components in a single event. Soft breakdown causes performance degradation or parameter decline in components, which is difficult to detect before the product leaves the factory, creating potential hazards. Static electricity is generated in the following ways, which will be introduced below to avoid situations where static electricity is the culprit.
1. Contact Friction Separation Charging-When two different objects come into contact and rub against each other, they generate equal amounts of opposite charges. This type of charging occurs extensively in various industries and daily life.
2. Electrostatic Induction Charging-When a neutral object approaches a charged object, or a charged object moves close to a neutral object, due to the electric field of the charged object, the neutral object develops a charge of opposite polarity at the end closest to the charged object, and a charge of the same polarity at the end furthest away. This type of charging is quite common.
3. Electromagnetic Induction Charging-Modern industrial and daily life power and lighting electricity all utilize the principle of electromagnetic induction power generation. Electrostatic technology applications also utilize the principle of electromagnetic induction power generation to convert low-voltage electricity into high-voltage electricity.
4. Air Charging by Radiation Ionization-Air and insulators, when irradiated by radioactive isotopes α, β, and γ rays, will cause neutral molecules to ionize and become charged.
5. Charging by Changes in the Three States of Matter-Water is a good conductor. Below 4°C, water changes from liquid to solid. When it freezes, the ice is charged. Liquid water changes to water vapor, which is also charged. Water vapor, when rising and condensing into water droplets, snow, or hail, is also electrically charged.
6. Molecular splitting electrification-Deformation, breakage, and fracture of an object cause neutral molecules to split and become charged. Sometimes, sparks may even appear at the moment of sudden breakage.
7. Polarization electrification-In an electric field, the positive and negative charges of some uncharged dielectrics will slightly shift in opposite directions under the influence of the electric field force. For most polarizable molecules, their dipoles must align in a specific direction, resulting in one end being negatively charged and the other positively charged. This is commonly known as dielectric polarization. Some dielectrics become polarized when a certain pressure is applied, and their dipole moments tilt when an electric field is applied. The former is the piezoelectric effect, and the latter is the piezoelectric heating effect, collectively known as piezoelectric polarization. Some dielectrics permanently retain their polarization even in the absence of an external electric field, creating an electric field around them; such objects are called electrets. Electrets, depending on their fabrication methods, can be classified into thermal electrets, electric electrets, optical electrets, radioactive electrets, and electromagnetic electrets.
8. Field Emission: In any electric field, a particle becomes an electric dipole. If the electric field strength is very high, electrons in the particle may be drawn out from the negative end by the high electric field, a phenomenon called electron field emission. Alternatively, positive ions in the particle may be drawn out from the positive end, a phenomenon called positive terminal field emission. This method can be used to obtain a large number of electrons in a short time. Electron field emission pulse systems can be used for short pulses of X-rays and for exposure in high-speed photography.