What can we do with an electrostatic machine?
Van de Graaff generator
Other electrostatic machines like the Wimshurst machine or Bonetti machine work similarly to the Van De Graaff; charge is transported by moving plates, disks, or cylinders to a high voltage electrode. For these generators, however, corona discharge from exposed metal parts at high potentials and poorer insulation result in smaller voltages. In an electrostatic generator, the rate of charge transported (current) to the high-voltage electrode is very small. After the machine is started, the voltage on the terminal electrode increases until the leakage current from the electrode equals the rate of charge transport. Therefore, leakage from the terminal determines the maximum voltage attainable. In the Van de Graaff generator, the belt allows the transport of charge into the interior of a large hollow spherical electrode. This is the ideal shape to minimize leakage and corona discharge, so the Van de Graaff generator can produce the greatest voltage. This is why the Van de Graaff design has been used for all electrostatic particle accelerators. In general, the larger the diameter and the smoother the sphere is, the higher the voltage that can be achieved.
Headphones
Electrostatic drivers consist of a thin, electrically charged diaphragm, typically a coated PET film membrane, suspended between two perforated metal plates (electrodes). The electrical sound signal is applied to the electrodes creating an electrical field; depending on the polarity of this field, the diaphragm is drawn towards one of the plates. Air is forced through the perforations; combined with a continuously changing electrical signal driving the membrane, a sound wave is generated. Electrostatic headphones are usually more expensive than moving-coil ones, and are comparatively uncommon. In addition, a special amplifier is required to amplify the signal to deflect the membrane, which often requires electrical potentials in the range of 100 to 1000 volts.
Electromagnetic suspension
According to Earnshaw's Theorem a paramagnetically magnetised body cannot rest in stable equilibrium when placed in any combination of gravitational and magnetostatic fields. In these kinds of fields an unstable equilibrium condition exists. Although static fields cannot give stability, EMS works by continually altering the current sent to electromagnets to change the strength of the magnetic field and allows a stable levitation to occur. In EMS a feedback loop which continuously adjusts one or more electromagnets to correct the object's motion is used to cancel the instability.
Electrostatic coating
Electrostatic coating is a manufacturing process that employs charged particles to more efficiently paint a workpiece. Paint, in the form of either powdered particles or atomized liquid, is initially projected towards a conductive workpiece using normal spraying methods, and is then accelerated toward the work piece by a powerful electrostatic charge.
Electromagnetic propulsion
There are multiple applications for EMP technologies in the field of aerospace. Many of these applications are conceptual as of now, however, there are also several applications that range from near term to next century. One of such applications is the use of EMP to control fine adjustments of orbiting satellites. One of these particular systems is based on the direct interactions of the vehicle's own electromagnetic field and the magnetic field of the Earth. The thrust force may be thought of as an electrodynamic force of interaction of the electric current inside its conductors with the applied natural field of the Earth. To attain a greater force of interaction, the magnetic field must be propagated further from the flight craft. The advantages of such systems is the very precise and instantaneous control over the thrust force. In addition, the expected electrical efficiencies are far greater than those of current chemical rockets that attain propulsion through the intermediate use of heat; this results in low efficiencies and large amounts of gaseous pollutants. The electrical energy in the coil of the EMP system is translated to potential and kinetic energy through direct energy conversion. This results in the system having the same high efficiencies as other electrical machines while excluding the ejection of any substance into the environment.
EMMA (accelerator)
The Electron Machine with Many Applications or Electron Model for Many Applications (EMMA) is a linear non-scaling FFAG (Fixed Field Alternating Gradient) particle accelerator at Daresbury Laboratory in the UK that can accelerate electrons from 10 to 20 MeV. A FFAG is a type of accelerator in which the magnetic field in the bending magnets is constant during acceleration. This means the particle beam will move radially outwards as its momentum increases. Acceleration was successfully demonstrated in EMMA, paving the way for future non-scaling FFAGs to meet important applications in energy, security and medicine.
Nano spray dryer
The electrostatic particle collector charges the dry particles' surface and deflects them with an electrical field. To produce the electrical field, a high voltage (16 kV) is applied to a round collector tube. The electrical field builds up between the inner wall of the collector tube and the tips of a grounded star electrode. To have a low level of energy in the system the current is very low.
Electrostatics
Static electricity is commonly used in xerography, air filters, and some automotive paints.
Static electricity is a buildup of electric charges on two objects that have become separated from each other.
Small electrical components can easily be damaged by static electricity. Component manufacturers use a number of antistatic devices to avoid this.
Anaesthetic machine
Older machines may lack some of the safety features and refinements present on newer machines. However, they were designed to be operated without mains electricity, using compressed gas power for the ventilator and suction apparatus. Modern machines often have battery backup, but may fail when this becomes depleted.
Electrophorus
The electrophorus is thus actually a manually operated electrostatic generator, using the same principle of electrostatic induction as electrostatic machines such as the Wimshurst machine and the Van de Graaff generator.
Loudspeaker
Electrostatic loudspeakers use a high voltage electric field (rather than a magnetic field) to drive a thin statically charged membrane. Because they are driven over the entire membrane surface rather than from a small voice coil, they ordinarily provide a more linear and lower-distortion motion than dynamic drivers. They also have a relatively narrow dispersion pattern that can make for precise sound-field positioning. However, their optimum listening area is small and they are not very efficient speakers. They have the disadvantage that the diaphragm excursion is severely limited because of practical construction limitations—the further apart the stators are positioned, the higher the voltage must be to achieve acceptable efficiency. This increases the tendency for electrical arcs as well as increasing the speaker's attraction of dust particles. Arcing remains a potential problem with current technologies, especially when the panels are allowed to collect dust or dirt and are driven with high signal levels.
Electroporation
Electroporation is performed with electroporators, purpose-built appliances which create an electrostatic field in a cell solution. The cell suspension is pipetted into a glass or plastic cuvette which has two aluminium electrodes on its sides. For bacterial electroporation, typically a suspension of around 50 microliters is used. Prior to electroporation, this suspension of bacteria is mixed with the plasmid to be transformed. The mixture is pipetted into the cuvette, the voltage and capacitance are set, and the cuvette is inserted into the electroporator. The process requires direct contact between the electrodes and the suspension. Immediately after electroporation, one milliliter of liquid medium is added to the bacteria (in the cuvette or in an Eppendorf tube), and the tube is incubated at the bacteria's optimal temperature for an hour or more to allow recovery of the cells and expression of the plasmid, followed by bacterial culture on agar plates.
Thermostat
Electromechanical thermostats use resistance elements as anticipators. Most electronic thermostats use either thermistor devices or integrated logic elements for the anticipation function. In some electronic thermostats, the thermistor anticipator may be located outdoors, providing a variable anticipation depending on the outdoor temperature. Thermostat enhancements include outdoor temperature display, programmability, and system fault indication. While such 24 volt thermostats are incapable of operating a furnace when the mains power fails, most such furnaces require mains power for heated air fans (and often also hot-surface or electronic spark ignition) rendering moot the functionality of the thermostat. In other circumstances such as piloted wall and "gravity" (fanless) floor and central heaters the low voltage system described previously may be capable of remaining functional when electrical power is unavailable.
Electrostatic lens
An electrostatic lens is a device that assists in the transport of charged particles. For instance, it can guide electrons emitted from a sample to an electron analyzer, analogous to the way an optical lens assists in the transport of light in an optical instrument. Systems of electrostatic lenses can be designed in the same way as optical lenses, so electrostatic lenses easily magnify or converge the electron trajectories. An electrostatic lens can also be used to focus an ion beam, for example to make a microbeam for irradiating individual cells.
Electrostatic force microscope
A common form of electric force microscopy involves a noncontact AFM mode of operation. In this mode the cantilever is oscillated at a resonant frequency of the cantilever and the AFM tip is held such that it only senses with long range electrostatic forces without entering the repulsive contact regime. In this non-contact regime, the electric force gradient causes a shift in the resonance frequency of the cantilever. EFM images can be created by measuring the cantilever oscillation, phase and/or frequency shift of the cantilever in response to the electrostatic force gradient.
Electromagnetic compatibility
Electrostatic discharge testing is typically performed with a piezo spark generator called an "ESD pistol". Higher energy pulses, such as lightning or nuclear EMP simulations, can require a large current clamp or a large antenna which completely surrounds the DUT. Some antennas are so large that they are located outdoors, and care must be taken not to cause an EMP hazard to the surrounding environment.
Electrostatic–pneumatic activation
Moreover, mechanical advantage is possible by use of electrostatic-pneumatic actuation. Since the cavity is filled with air, mechanical amplification is lower than hydraulic machinery with a non-compressible fluid.
Electrostatic deflection
Electrostatic deflection refers to a technique for modifying the path of a beam of charged particles by the use of an electric field applied transverse to the path of the particles. The technique is called electro"static" because the strength and direction of the applied field changes slowly relative to the time it takes for the particles to transit the field, and thus can be considered not to change (be static) for any particular particle.
The Lorentz force acts on any charged particle in an electromagnetic field. Electrostatic deflection uses a special, simplified case of this general effect by limiting the field to an electric field. An electric field applies a force on a particle that is proportional to the strength of the field and to the charge on the particle. The direction of the applied force is the same as the direction of the electric field. For electrostatic deflection, the applied electric field is arranged so that it lies in the plane perpendicular to the initial direction of the stream. The particles are accelerated by this force in proportion to the charge of the particles. The path the particles follow depends on their sideways acceleration and their velocity when they enter the deflecting field. Therefore, it is important for good control of the direction that the particles in the stream have a uniform charge-to-mass ratio and that they move at a uniform speed. 
The most common use for this technique is controlling the path of a stream of electrons in a vacuum. One application is in small cathode ray tubes for oscilloscopes. In these tubes the electric field is created by two sets of paired electrodes, mounted at right angles, that the electron stream flows between. This arrangement allows independent deflection of the beam in two dimensions (usually perceived as up/down (vertical) and right/left (horizontal)). The electrodes are commonly called "deflection plates". Traditionally, the electrons pass through the vertical deflection plates first, yielding slightly higher sensitivity because of the longer travel time from the vertical deflection plates to the phosphor screen as compared to the horizontal deflection plates. In very high speed oscilloscopes, the deflection plates were often complex structures, combining a series of sub-plates with an electrical delay line. By matching the propagation speed of the electrical signal with the transit speed of the electrons, maximum bandwidth (frequency response) was achieved.
Gaston Planté
Planté also investigated the differences between static electricity and dynamic electricity (i.e., from batteries). As part of this investigation, Planté invented a mechanical device that he called the Rheostatic Machine. The Rheostatic Machine used a bank of mica capacitors, a clever rotating commutator, and a series of contacts to alternately charge a bank of capacitors in parallel (from a high-voltage battery source) and then connect the capacitors in series. This arrangement multiplied the battery voltage by the number of capacitor stages to obtain very high voltages. By rapidly rotating the shaft, a series of high-voltage sparks many centimetres long could be rapidly generated. This device was a mechanical predecessor of the modern-day Marx generator. Using this device, Planté explored the electrical breakdown of air, the formation of Lichtenberg figures, and the behaviour of thin wires when pulsed by high electric currents.
Electrostatic discharge
Due to dielectric nature of electronics component and assemblies, electrostatic charging can not be completely prevented during handling of devices. Most of ESD sensitive electronic assemblies and components are also so small that manufacturing and handling is done with automated equipment. ESD prevention activities are therefore important with those processes where components come into direct contact with equipment surfaces. In addition, it is important to prevent ESD when an electrostatic discharge sensitive component is connected with other conductive parts of the product itself. An efficient way to prevent ESD is to use materials that are not too conductive but will slowly conduct static charges away. These materials are called static dissipative and have resistivity values below 10 ohm-meters. Materials in automated manufacturing which will touch on conductive areas of ESD sensitive electronic should be made of dissipative material, and the dissipative material must be grounded.
Electrostatic detection device
An electrostatic detection device, EDD or ESDA, is a specialized piece of equipment commonly used in questioned document examination to reveal indentations or impressions in paper that may otherwise go unnoticed. It is a non-destructive technique (will not damage the evidence in question), allowing further tests to be carried out. It is a sensitive technique capable of detecting indentations on pages several layers below the top sheet and many years after the indentations were created.
Stop action magnet
Whilst hand registering the organ is often carried out, this can only be used to facilitate small changes in the overall tonal colour, due to physical restrictions. i.e. The operator cannot operate more than one or two devices simultaneously, especially when using only one hand for registration, whilst playing keys with the other hand! This is where the true versatility of the SAM comes into play. By applying a low voltage electric current (usually between 12 and 30 volts at up to 0.5 ampere) to one or the other of a SAM's electromagnets (coils) the armature can be made to follow the same movement and thus operate its switching contact/s as if it had been actuated by a human operator. The advantage of electrical operation being that many SAMs can be electrically connected together and switched by the use of a single button (piston) depressed by the human player using only one finger. It can therefore be seen that operating many SAMs in simultaneous combination will have a far greater instantaneous effect on the sound of the organ (which is essential for tonal variety) than is achievable by the use of single SAMs. Furthermore, combinations of registration changes can be stored in electronic or electromechanical memory which forms part of the organ's combination action, for instant recall at the touch of a button (piston) and translated into electrical impulses used to operate multiple SAMs.
Electric toothbrush
An electric toothbrush is a toothbrush that makes rapid automatic bristle motions, either back-and-forth oscillation or rotation-oscillation (where the brush head alternates clockwise and counterclockwise rotation), in order to clean teeth. Motions at sonic speeds or below are made by a motor. In the case of ultrasonic toothbrushes, ultrasonic motions are produced by a piezoelectric crystal. A modern electric toothbrush is usually powered by a rechargeable battery charged through inductive charging when the brush sits in the charging base between uses.
Magnetism
Electromagnets are widely used as components of other electrical devices, such as motors, generators, relays, solenoids, loudspeakers, hard disks, MRI machines, scientific instruments, and magnetic separation equipment. Electromagnets are also employed in industry for picking up and moving heavy iron objects such as scrap iron and steel. Electromagnetism was discovered in 1820.
Electric motor
An electrostatic motor is based on the attraction and repulsion of electric charge. Usually, electrostatic motors are the dual of conventional coil-based motors. They typically require a high-voltage power supply, although very small motors employ lower voltages. Conventional electric motors instead employ magnetic attraction and repulsion, and require high current at low voltages. In the 1750s, the first electrostatic motors were developed by Benjamin Franklin and Andrew Gordon. Today, the electrostatic motor finds frequent use in micro-electro-mechanical systems (MEMS) where their drive voltages are below 100 volts, and where moving, charged plates are far easier to fabricate than coils and iron cores. Also, the molecular machinery that runs living cells is often based on linear and rotary electrostatic motors.
Electrostatic analyzer
The Face-Field Cylindrical Energy Analyzer is a very new class of electrostatic cylindrical energy analyzers. It uses a cylindrical field, restricted by concentric cylindrical electrodes and two flat electrodes perpendicular to the axis of symmetry. The inner electrode is usually connected with the flat electrodes, and the outer one, which is electrically isolated, has an electric potential that can either be constant or variable. (Potential is negative (-) for an electron beam, and positive (+) for a positive-ion beam.) The focusing field becomes very different from that of the simple-cylinder type (such as in the well-known CMA) near the flat-face boundaries; namely, it can achieve a very high energy resolution for a beam entering through the entrance window in one of the face electrodes. This new class of analyzer can be used in a variety of applications. It do remote sensing such as measuring the flow of charged particles in space; e.g., scanning-electron/Auger-electron spectroscopy for analyzing large objects.
Thermal management (electronics)
An electrostatic fluid accelerator (EFA) is a device which pumps a fluid such as air without any moving parts. Instead of using rotating blades, as in a conventional fan, an EFA uses an electric field to propel electrically charged air molecules. Because air molecules are normally neutrally charged, the EFA has to create some charged molecules, or ions, first. Thus there are three basic steps in the fluid acceleration process: ionize air molecules, use those ions to push many more neutral molecules in a desired direction, and then recapture and neutralize the ions to eliminate any net charge.
Magnetostatics
Magnetostatics is the study of magnetic fields in systems where the currents are steady (not changing with time). It is the magnetic analogue of electrostatics, where the charges are stationary. The magnetization need not be static; the equations of magnetostatics can be used to predict fast magnetic switching events that occur on time scales of nanoseconds or less. Magnetostatics is even a good approximation when the currents are not static — as long as the currents do not alternate rapidly. Magnetostatics is widely used in applications of micromagnetics such as models of magnetic recording devices. Magnetostatic focussing can be achieved either by a permanent magnet or by passing current through a coil of wire whose axis coincides with the beam axis.
Counter-IED equipment
Aerostats are balloons equipped with stabilized electro optical, infrared, and radar sensors which are manned 24 hours a day. The Persistent Threat Detection System (PTDS) is the largest and most capable Aerostat ever used in combat. First used in 2004 (Camp Slayer, Iraq). It can sit for months thousands of feet above a base. Known as the "unblinking eye", Aerostats provide real-time High Definition imagery of the surrounding area, day or night, and are strategically placed for surveillance purposes. They enhance situational awareness and improve force protection. Aerostats can be used to reconnoiter routes before friendly forces travel them and to provide over watch for dismounted troops or convoys. They can also serve as a communications and Full Motion Video (FMV) relay platform to extend the range and disseminate situational awareness. They are linked with several ground-based sensors, including acoustic sensors that detect and locate weapon fire or blasts.
Electrostatic motor
Also, the molecular machinery which runs living cells is often based on linear and rotary electrostatic motors.
Mesoscale manufacturing
Electrical discharge machining (EDM) is another subtractive manufacturing process used in the mesoscale. This process requires that electricity be transferred between the tool electrode and the work piece and therefore it can only be used to manufacture materials that conduct electricity. One advantage of EDM is that it can be used on hard materials that do not work well in traditional machining processes, such as titanium.
Electron diffraction
Electron diffraction is most frequently used in solid state physics and chemistry to study the crystal structure of solids. Experiments are usually performed in a transmission electron microscope (TEM), or a scanning electron microscope (SEM) as electron backscatter diffraction. In these instruments, electrons are accelerated by an electrostatic potential in order to gain the desired energy and determine their wavelength before they interact with the sample to be studied.
Anaesthetic machine
An anaesthetic machine (British English) or anesthesia machine (American English; see spelling differences) is a medical device used to generate and mix a fresh gas flow of medical gases and inhalational anaesthetic agents for the purpose of inducing and maintaining anaesthesia.
Electrostatic spray-assisted vapour deposition
Electrostatic spray-assisted vapour deposition (ESAVD) is a technique (developed by a company called IMPT) to deposit both thin and thick layers of a coating onto various substrates. In simple terms chemical precursors are sprayed across an electrostatic field towards a heated substrate, the chemicals undergo a controlled chemical reaction and are deposited on the substrate as the required coating. Electrostatic spraying techniques were developed in the 1950s for the spraying of ionised particles on to charged or heated substrates.
Electrodynamic tether
An electrodynamic tether is attached to an object, the tether being oriented at an angle to the local vertical between the object and a planet with a magnetic field. The tether's far end can be left bare, making electrical contact with the ionosphere. When the tether intersects the planet's magnetic field, it generates a current, and thereby converts some of the orbiting body's kinetic energy to electrical energy. Functionally, electrons flow from the space plasma into the conductive tether, are passed through a resistive load in a control unit and are emitted into the space plasma by an electron emitter as free electrons. As a result of this process, an electrodynamic force acts on the tether and attached object, slowing their orbital motion. In a loose sense, the process can be likened to a conventional windmill- the drag force of a resistive medium(air or, in this case, the magnetosphere) is used to convert the kinetic energy of relative motion(wind, or the satellite's momentum) into electricity. In principle, compact high-current tether power generators are possible and, with basic hardware, tens, hundreds, and thousands of kilowatts appears to be attainable.
Electrostatic discharge
ESD can cause harmful effects of importance in industry, including explosions in gas, fuel vapor and coal dust, as well as failure of solid state electronics components such as integrated circuits. These can suffer permanent damage when subjected to high voltages. Electronics manufacturers therefore establish electrostatic protective areas free of static, using measures to prevent charging, such as avoiding highly charging materials and measures to remove static such as grounding human workers, providing antistatic devices, and controlling humidity.
Electrostatic loudspeaker
The directionality of electrostatics can also be a disadvantage in that it means the 'sweet spot' where proper stereo imaging can be heard is relatively small, limiting the number of people who can fully enjoy the advantages of the speakers simultaneously. In 1992 Critical Mass introduced the first electrostatic speakers for use in the mobile environment (car audio). Critical Mass engineer and CEO Wayde Alfarone's design capitalized on the directional nature of electrostats by creating separate sound fields for different seating locations in the vehicle.
Electrolysis
Electrolysis is also used in the cleaning and preservation of old artifacts. Because the process separates the non-metallic particles from the metallic ones, it is very useful for cleaning a wide variety of metallic objects, from old coins to even larger objects including rusted cast iron cylinder blocks and heads when rebuilding automobile engines. Rust removal from small iron or steel objects by electrolysis can be done in a home workshop using simple materials such as a plastic bucket, tap water, lengths of rebar, washing soda, baling wire, and a battery charger.
Magnet wire
Electric motors convert electrical energy into mechanical motion, usually through the interaction of magnetic fields and current-carrying conductors. Electric motors are found in numerous diverse applications, such as fans, blowers, pumps, machines, household appliances, power tools, and disk drives. The very largest electric motors with ratings in the thousands of kilowatts are used in such applications as the propulsion of large ships. The smallest motors move the hands in electric wristwatches.
Electrovibration
An electrostatic force is created by applying a time-varying voltage between an electrode and an insulated ground plane. When a finger scans over an insulated plate with a time-varying voltage, the finger works as the induced ground plane. The induced static electricity creates an electric force field between the finger and the surface. 
A parallel-plate capacitor model can be used to approximate the skin–surface interface. The electrode acts as one plate, while the conductive subcutaneous layer in the skin acts as the other, thus representing a hybrid natural/artificial electrostatic actuator. The following equation approximates the electrostatic force experienced between the finger and the electrode:
Electrostatic precipitator
An electrostatic precipitator (ESP) is a filtration device that removes fine particles, like dust and smoke, from a flowing gas using the force of an induced electrostatic charge minimally impeding the flow of gases through the unit.
Spray painting
Electrostatic painting was first patented in the U.S. by Harold Ransburg in the late 1940s. Harold Ransburg founded Ransburg Electrostatic Equipment and discovered that electrostatic spray painting was an immediate success as manufacturers quickly perceived the substantial materials savings that could be achieved. In electrostatic spray painting or powder coating, the atomized particles are made to be electrically charged, thereby repelling each other and spreading themselves evenly as they exit the spray nozzle. The object being painted is charged oppositely or grounded. The paint is then attracted to the object giving a more even coat than wet spray painting, and also greatly increasing the percentage of paint that sticks to the object. This method also means that paint covers hard to reach areas. The whole may then be baked to properly attach the paint: the powder turns into a type of plastic. Car body panels and bike frames are two examples where electrostatic spray painting is often used.
Electrostatic motor
An electrostatic motor or capacitor motor is a type of electric motor based on the attraction and repulsion of electric charge.
Neural engineering
Neuroprosthetics are devices capable of supplementing or replacing missing functions of the nervous system by stimulating the nervous system and recording its activity. Electrodes that measure firing of nerves can integrate with prosthetic devices and signal them to perform the function intended by the transmitted signal. Sensory prostheses use artificial sensors to replace neural input that might be missing from biological sources (He 2005). Engineers researching these devices are charged with providing a chronic, safe, artificial interface with neuronal tissue. Perhaps the most successful of these sensory prostheses is the cochlear implant which has restored hearing abilities to the deaf. Visual prosthesis for restoring visual capabilities of blind persons is still in more elementary stages of development. Motor prosthesics are devices involved with electrical stimulation of biological neural muscular system that can substitute for control mechanisms of the brain or spinal cord. Smart prostheses can be designed to replace missing limbs controlled by neural signals by transplanting nerves from the stump of an amputee to muscles. Electrodes placed on the skin can interpret signals and then control the prosthetic limb. These prosthetics have been very successful. Functional electrical stimulation (FES) is a system aimed at restoring motor processes such as standing, walking, and hand grasp.
Electrorheological fluid
There are two main theories to explain the effect: the interfacial tension or 'water bridge' theory, and the electrostatic theory. The water bridge theory assumes a three phase system, the particles contain the third phase which is another liquid (e.g. water) immiscible with the main phase liquid (e.g. oil). With no applied electric field the third phase is strongly attracted to and held within the particles. This means the ER fluid is a suspension of particles, which behaves as a liquid. When an electric field is applied the third phase is driven to one side of the particles by electro osmosis and binds adjacent particles together to form chains. This chain structure means the ER fluid has become a solid. The electrostatic theory assumes just a two phase system, with dielectric particles forming chains aligned with an electric field in an analogous way to how magnetorheological fluid (MR) fluids work. An ER fluid has been constructed with the solid phase made from a conductor coated in an insulator. This ER fluid clearly cannot work by the water bridge model. However, although demonstrating that some ER fluids work by the electrostatic effect, it does not prove that all ER fluids do so. The advantage of having an ER fluid which operates on the electrostatic effect is the elimination of leakage current, i.e. potentially there is no direct current. Of course, since ER devices behave electrically as capacitors, and the main advantage of the ER effect is the speed of response, an alternating current is to be expected.
Microscanner
Electrostatic actuators offer high power similar to electromagnetic drives. In contrast to an electromagnetic drive, the resulting drive force between the drive structures cannot be reversed in polarity. For the realization of quasi-static components with positive and negative effective direction, two drives with positive and negative polarity are required. As a rule of thumb, vertical comb drives are utilized here. Nevertheless, the highly non-linear drive characteristics in some parts of the deflection area can be hindering for controlling the mirror properly. For that reason many highly developed microscanners today utilize a resonant mode of operation, where an Eigenmode is activated. Resonant operation is most energy efficient. For beam positioning and applications which are to be static-actuated or linearized-scanned, quasi-static drives are required and therefore of great interest.
Electric machine
An electric motor converts electrical energy into mechanical energy. The reverse process of electrical generators, most electric motors operate through interacting magnetic fields and current-carrying conductors to generate rotational force. Motors and generators have many similarities and many types of electric motors can be run as generators, and vice versa.
Electric motors are found in applications as diverse as industrial fans, blowers and pumps, machine tools, household appliances, power tools, and disk drives. They may be powered by direct current or by alternating current which leads to the two main classifications: AC motors and DC motors.
Electrostatic generator
The Van de Graaff generator was invented by American physicist Robert J. Van de Graaff in 1929 at MIT as a particle accelerator. The first model was demonstrated in October 1929. In the Van de Graaff machine, an insulating belt transports electric charge to the interior of an insulated hollow metal high voltage terminal, where it is transferred to the terminal by a "comb" of metal points. The advantage of the design was that since there was no electric field in the interior of the terminal, the charge on the belt could continue to be discharged onto the terminal regardless of how high the voltage on the terminal was. Thus the only limit to the voltage on the machine is ionization of the air next to the terminal. This occurs when the electric field at the terminal exceeds the dielectric strength of air, about 30 kV per centimeter. Since the highest electric field is produced at sharp points and edges, the terminal is made in the form of a smooth hollow sphere; the larger the diameter the higher the voltage attained. The first machine used a silk ribbon bought at a five and dime store as the charge transport belt. In 1931 a version able to produce 1,000,000 volts was described in a patent disclosure.
Electrostatics
Natural electrostatic phenomena are most familiar as an occasional annoyance in seasons of low humidity, but can be destructive and harmful in some situations (e.g. electronics manufacturing). When working in direct contact with integrated circuit electronics (especially delicate MOSFETs), or in the presence of flammable gas, care must be taken to avoid accumulating and suddenly discharging a static charge (see electrostatic discharge).
Electromagnetic field
Thus, electrostatics, as well as magnetism and magnetostatics, are now seen as studies of the static EM field when a particular frame has been selected to suppress the other type of field, and since an EM field with both electric and magnetic will appear in any other frame, these "simpler" effects are merely the observer's. The "applications" of all such non-time varying (static) fields are discussed in the main articles linked in this section.
Edward Nairne
Nairne patented several electrical machines, including an electrostatic generator consisting of a glass cylinder mounted on glass insulators; the device can supply either positive or negative electricity, and was intended for medicinal use. In the eighth edition of the instruction manual for this device he claimed that "electricity is almost a specific in some disorders, and deserves to be held in the highest estimation for its efficacy in many others". He recommended its use for nervous disorders, bruises, burns, scales, bloodshot eyes, toothache, sciatica, epilepsy, hysteria, agues and so on. He also made improvements to the Cuff microscope, building it into a portable case and calling it a chest microscope.
Electrical discharge machining
Electrical discharge machining (EDM), also known as spark machining, spark eroding, burning, die sinking, wire burning or wire erosion, is a manufacturing process whereby a desired shape is obtained by using electrical discharges (sparks). Material is removed from the work piece by a series of rapidly recurring current discharges between two electrodes, separated by a dielectric liquid and subject to an electric voltage. One of the electrodes is called the tool-electrode, or simply the "tool" or "electrode," while the other is called the workpiece-electrode, or "work piece." The process depends upon the tool and work piece not making actual contact.
Electrostatic motor
In 2004 researchers at University of California, Berkeley, developed rotational bearings based upon multiwall carbon nanotubes. By attaching a gold plate (with dimensions of the order of 100 nm) to the outer shell of a suspended multiwall carbon nanotube (like nested carbon cylinders), they are able to electrostatically rotate the outer shell relative to the inner core. These bearings are very robust; devices have been oscillated thousands of times with no indication of wear. These nanoelectromechanical systems (NEMS) represent a promising direction in miniaturization and may find their way into commercial applications in the future.
Electrostatic generator
In 1878, the British inventor James Wimshurst started his studies about electrostatic generators, improving the Holtz machine, in a powerful version with multiple disks. The classical Wimshurst machine, that became the most popular form of influence machine, was reported to the scientific community by 1883, although previous machines with very similar structures were previously described by Holtz and Musaeus. In 1885, one of the largest-ever Wimshurst machines was built in England (it is now at the Chicago Museum of Science and Industry). The Wimshurst machine is a considerably simple machine; it works, as all influence machines, with electrostatic induction of charges, which means that it uses even the slightest existing charge to create and accumulate more charges, and repeats this process for as long as the machine is in action. Wimshurst machines are composed of: two insulated disks attached to pulleys of opposite rotation, the disks have small conductive (usually metal) plates on their outward-facing sides; two double-ended brushes that serve as charge stabilizers and are also the place where induction happens, creating the new charges to be collected; two pairs of collecting combs, which are, as the name implies, the collectors of electrical charge produced by the machine; two Leyden Jars, the capacitors of the machine; a pair of electrodes, for the transfer of charges once they have been sufficiently accumulated. The simple structure and components of the Wimshurst Machine make it a common choice for a homemade electrostatic experiment or demonstration, these characteristics were factors that contributed to its popularity, as previously mentioned.
Static electricity
Static electricity is commonly used in xerography, air filters (particularly electrostatic precipitators), paint sprayers, powder testing.
Electrostatic plotter
Electrostatic plotters can print in black and white or in color. Some models handle paper sizes up to six feet wide. Newer versions are large-format laser printers and focus light onto a charged drum using lasers or LEDs. The image quality produced by some electrostatic plotters was lower than that of contemporary pen plotters, but the increased speed and economy made them useful. Unlike a pen plotter, the plot time of a rasterized electrostatic plotter was independent of the level of detail of the image. Modern electrostatic color plotters are found in the short run graphics industry, printing on a variety of paper or plastic film surfaces.
Pneumatic exercise equipment
Pneumatic exercise equipment or - machine is a device used for physical exercise. The difference to regular weights or exercise equipment is that the weight stacks, wires and other moving parts are replaced with a pneumatic cylinder whose resistance can be adjusted with air pressure. Modern machines with repetition counters and electrical pressure valves promote precise training of certain muscle groups or a sector of physical functions affecting ones quality of life. Guidelines for health exercise can also be the purpose of training which can be pursued and monitored by loading a training program to a Smart Card and accomplish exercises guided by machines themselves.Using pneumatic cylinders in exercise machines is a rather new innovation. First prototypes were born during the 80's and 90's.
Electrostatic spray ionization
Electrostatic spray ionization (ESTASI) is an ambient ionization method for mass spectrometry (MS) analysis of samples located on a flat or porous surface, or inside a microchannel. It was developed in 2011 by Professor Hubert H. Girault’s group at the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland. In a typical ESTASI process, a droplet of a protic solvent containing analytes is deposited on a sample area of interest which itself is mounted to an insulating substrate. Under this substrate and right below the droplet, an electrode is placed and connected with a pulsed high voltage (HV) to electrostatically charge the droplet during pulsing. When the electrostatic pressure is larger than the surface tension, droplets and ions are sprayed. ESTASI is a contactless process based on capacitive coupling. One advantage of ESTASI is, that the electrode and sample droplet act contact-less avoiding thereby any oxidation or reduction of the sample compounds at the electrode surface, which often happens during standard electrospray ionization (ESI). ESTASI is a powerful new ambient ionization technique that has already found many applications in the detection of different analytes, such as organic molecules, peptides and proteins with molecule weight up to 70 kDa. Furthermore, it was used to couple MS with various separation techniques including capillary electrophoresis and gel isoelectric focusing, and it was successfully applied under atmospheric pressure to the direct analysis of samples with only few preparation steps.
Van de Graaff generator
A Van de Graaff generator is an electrostatic generator which uses a moving belt to accumulate electric charge on a hollow metal globe on the top of an insulated column, creating very high electric potentials. It produces very high voltage direct current (DC) electricity at low current levels. It was invented by American physicist Robert J. Van de Graaff in 1929. 
The potential difference achieved by modern Van de Graaff generators can be as much as 5 megavolts. A tabletop version can produce on the order of 100,000 volts and can store enough energy to produce a visible spark. Small Van de Graaff machines are produced for entertainment, and for physics education to teach electrostatics; larger ones are displayed in some science museums.
Electromagnetic brake
Electrical hysteresis units have an extremely wide torque range. Since these units can be controlled remotely, they are ideal for test stand applications where varying torque is required. Since drag torque is minimal, these units offer the widest available torque range of any of the hysteresis products. Most applications involving powered hysteresis units are in test stand requirements.
Antistatic device
Ionizing bars are most commonly suspended above a conveyor belt or other apparatus in a production line where the product can pass below it; the distance is usually calibrated for the specific application. The bar works by emitting an ionized corona onto the products below it. If then a product on the line has a positive or negative static charge, as it passes through the ionized aura created by the bar, it will attract the correspondingly charged positive or negative ions and become electrically neutral.
Electrostatic force microscope
Electrostatic force microscopy (EFM) is a type of dynamic non-contact atomic force microscopy where the electrostatic force is probed. ("Dynamic" here means that the cantilever is oscillating and does not make contact with the sample). This force arises due to the attraction or repulsion of separated charges. It is a long-range force and can be detected 100 nm or more from the sample. 
For example, consider a conductive cantilever tip and sample which are separated a distance "z" usually by a vacuum. A bias voltage between tip and sample is applied by an external battery forming a capacitor, "C", between the two. The capacitance of the system depends on the geometry of the tip and sample. The total energy stored in that capacitor is "U = ½ C⋅ΔV". The work done by the battery to maintain a constant voltage, "ΔV", between the capacitor plates (tip and sample) is "-2U". By definition, taking the negative gradient of the total energy "U = -U" gives the force. The "z" component of the force (the force along the axis connecting the tip and sample) is thus:
Electrostatic voltmeter
It can accurately measure surface potential (voltage) on materials without making physical contact and so there is no electrostatic charge transfer or loading of the voltage source.
Air shower (room)
Often, air showers are equipped with air ionizers to reduce static electricity, as large volumes of high-velocity air create electric charges. Since laboratory equipment, electronic measuring instruments and many hi-tech manufactured goods can often be damaged by electrostatic discharge, ionizers are essential in rendering material surfaces electrically neutral prior to entering the cleanroom.
Electric machine
It is usually possible to overload electric machines for a short time until the current in the coils heats parts of the machine to a temperature which cause damage. PM machines can in less degree be subjected to such overload because too high current in the coils can create a magnetic field strong enough to demagnetise the magnets.
Electrospray ionization
Electrospray ionization (ESI) is a technique used in mass spectrometry to produce ions using an electrospray in which a high voltage is applied to a liquid to create an aerosol. It is especially useful in producing ions from macromolecules because it overcomes the propensity of these molecules to fragment when ionized. ESI is different from other ionization processes (e.g. matrix-assisted laser desorption/ionization (MALDI)) since it may produce multiple-charged ions, effectively extending the mass range of the analyser to accommodate the kDa-MDa orders of magnitude observed in proteins and their associated polypeptide fragments.
Electrostatic motor
Electric motors, in general, produce motion when powered by electric currents. The common type of spacecraft ion drive uses electrostatic forces to accelerate ions to generate forces to create motion, and thus can be considered as unconventional electric motors.
Electrohydrodynamics
In the first instance, shaped electrostatic fields (ESF's) create hydrostatic pressure (HSP, or motion) in dielectric media. When such media are fluids, a flow is produced. If the dielectric is a vacuum or a solid, no flow is produced. Such flow can be directed against the electrodes, generally to move the electrodes. In such case, the moving structure acts as an electric motor. Practical fields of interest of EHD are the common air ioniser, electrohydrodynamic thrusters and EHD cooling systems.
Electrostatic plotter
An electrostatic plotter is a type of plotter that draws images on paper with an electrostatic process. They are most frequently used for Computer-Aided Engineering (CAE), producing raster images via either a Liquid Toner or a Dry Toner model.
Electrostatics
In other words, electrostatics does not require the absence of magnetic fields or electric currents. Rather, if magnetic fields or electric currents "do" exist, they must not change with time, or in the worst-case, they must change with time only "very slowly". In some problems, both electrostatics and magnetostatics may be required for accurate predictions, but the coupling between the two can still be ignored. Electrostatics and magnetostatics can both be seen as Galilean limits for electromagnetism.
Electrostatic loudspeaker
Electrostatic speakers enjoy some popularity among do-it-yourself (DIY) loudspeaker builders. They are one of the few types of speakers in which the transducers themselves can be built from scratch by an amateur as basic hardware for complete ESL DIY projects can be found available online. Such supplies include resistors and capacitors for RC circuit frequency equalization, if necessary; step-up transformers; perforated metal sheets or grids and insulating plastics for the stators; polymer film and conductive paint (e.g. a liquid graphite suspension) for the membrane; simple tensioning equipment for proper membrane tuning; and a frame, usually of wood, to hold everything together. A widely read resource by ESL enthusiasts is "The Electrostatic Loudspeaker Design Cookbook" () by notable ESL specialist Roger Sanders.
Eddy current
Eddy current brakes use the drag force created by eddy currents as a brake to slow or stop moving objects. Since there is no contact with a brake shoe or drum, there is no mechanical wear. However, an eddy current brake cannot provide a "holding" torque and so may be used in combination with mechanical brakes, for example, on overhead cranes. Another application is on some roller coasters, where heavy copper plates extending from the car are moved between pairs of very strong permanent magnets. Electrical resistance within the plates causes a dragging effect analogous to friction, which dissipates the kinetic energy of the car. The same technique is used in electromagnetic brakes in railroad cars and to quickly stop the blades in power tools such as circular saws. Using electromagnets, as opposed to permanent magnets, the strength of the magnetic field can be adjusted and so the magnitude of braking effect changed.
Dynamo
The electric dynamo uses rotating coils of wire and magnetic fields to convert mechanical rotation into a pulsing direct electric current through Faraday's law of induction. A dynamo machine consists of a stationary structure, called the stator, which provides a constant magnetic field, and a set of rotating windings called the armature which turn within that field. Due to Faraday's law of induction the motion of the wire within the magnetic field creates an electromotive force which pushes on the electrons in the metal, creating an electric current in the wire. On small machines the constant magnetic field may be provided by one or more permanent magnets; larger machines have the constant magnetic field provided by one or more electromagnets, which are usually called "field coils".
Chuck (engineering)
Commonly used for holding silicon wafers during lithography processes, an "electrostatic chuck" comprises a metal base-plate and a thin dielectric layer; the metal base-plate is maintained at a high-voltage relative to the wafer, and so an electrostatic force clamps the wafer to it. Electrostatic chucks may have pins, or mesas, the height of which is included in the reported dielectric thickness; a design by Sandia National Laboratory uses a patterned silicon-dioxide dielectric to form the pins.
Electric machine
This machine can also be run by connecting the stator coils to the grid, and supplying the rotor coils with AC from an inverter. The advantage is that it is possible to control rotating speed of the machine with a fractionally rated inverter. When run this way the machine is known as a brushed double feed "induction" machine. "Induction" is misleading because there is no useful current in the machine which is set up by induction.
Electric machine
In "electrostatic machines", torque is created by attraction or repulsion of electric charge in rotor and stator.
Antistatic device
An ionizing bar, sometimes referred to as a static bar, is a type of industrial equipment used for removing static electricity from a production line to dissipate static cling and other such phenomena that would disrupt the line. It is important in the manufacturing and printing industries, although it can be used in other applications as well.
Electric machine
"Reluctance machines" have no windings in rotor, only a ferromagnetic material shaped so that "electromagnets" in stator can "grab" the teeth in rotor and move it a little. The electromagnets are then turned off, while another set of electromagnets is turned on to move stator further. Another name is step motor, and it is suited for low speed and accurate position control. Reluctance machines can be supplied with PMs in stator to improve performance. The “electromagnet” is then “turned off” by sending a negative current in the coil. When the current is positive the magnet and the current cooperate to create a stronger magnetic field which will improve the reluctance machine’s maximum torque without increasing the currents maximum absolute value.
Hall-effect thruster
The essential working principle of the Hall thruster is that it uses an electrostatic potential to accelerate ions up to high speeds. In a Hall thruster, the attractive negative charge is provided by an electron plasma at the open end of the thruster instead of a grid. A radial magnetic field of about 100–300 G (0.01–0.03 T) is used to confine the electrons, where the combination of the radial magnetic field and axial electric field cause the electrons to drift in azimuth thus forming the Hall current from which the device gets its name.
A schematic of a Hall thruster is shown in the adjacent image. An electric potential between 150 and 800 volts is applied between the anode and cathode.
ESD simulator
There are three distinct test models for electrostatic discharge: human-body, machine, and charged-devices models. The human-body model emulates the action of a human body discharging static electricity, the machine model simulates static discharge from a machine, and the charged-device model simulates the charging and discharging events that occur in production processes and equipment.
Franklin's electrostatic machine
Franklin's electrostatic machine is a high-voltage static electricity-generating device used by Benjamin Franklin in the mid-18th century for research into electrical phenomena. Its key components are a glass globe which turned on an axis via a crank, a cloth pad in contact with the spinning globe, a set of metal needles to conduct away the charge developed on the globe by its friction with the pad, and a Leyden jara high-voltage capacitorto accumulate the charge. Franklin's experiments with the machine eventually led to new theories about electricity and inventing the lightning rod.
Electron-beam machining
EBM equipment in construction is similar to electron beam welding machines (see electron beam welding).
EBM machines usually utilize voltages in the range of 150 to 200 kV to accelerate electrons to about 200,000 km/s. Magnetic lenses are used to focus the electron beam to the surface of the work-piece. By means of electromagnetic deflection system the beam is positioned as needed, usually by means of a computer.
Electro-hydraulic actuator
Electro-Hydrostatic actuators (EHAs), replace hydraulic systems with self-contained actuators operated solely by electrical power. EHAs eliminate the need for separate hydraulic pumps and tubing, simplifying system architectures and improving safety and reliability. This technology originally was developed for the aerospace industry but has since expanded into many other industries where hydraulic power is commonly used.
History of electromagnetic theory
In 1663 Otto von Guericke invented a device that is now recognized as an early (possibly the first) electrostatic generator, but he did not recognize it primarily as an electrical device or conduct electrical experiments with it. By the end of the 17th Century, researchers had developed practical means of generating electricity by friction with an electrostatic generator, but the development of electrostatic machines did not begin in earnest until the 18th century, when they became fundamental instruments in the studies about the new science of electricity.
Electrostatic coating
An addition to the electrostatic coating (or e-coating) process is dipping electrically conductive parts into a tank of paint that is then electrostatically charged. The ionic bond of the paint to the metal creates the paint coating, in which its thickness is directly proportional to the length of time the parts are left in the tank and the time the charge remains active. Once the parts are removed from the paint tank, they are rinsed off to remove any residual paint that is not ionically bonded, leaving a thin film of electrostatically bonded paint on the surface of the part.The workpiece travels down a conveyor belt towards a paint booth, or paint tank, where it is sprayed with, or dipped into, electrostatically charged paint particles. Integrated into a powder paint booth is a powder recovery unit, which recovers between 95% and 100% of the paint over-spray coatings. After the workpiece is coated, it continues on the conveyor belt to an oven, where the paint is cured. The benefits to the process of electrostatic coating is the ability to recover the little over-spray and having the process automated which will cut costs. The reason for the little over spray is the paint particles that do not hit the piece will turn in the air and go back to the piece. There are also some drawbacks to the process: everything in the area of the coating must be grounded to prevent static buildup and can easily arc, damaging the hanging devices and/or the locations where the hanging devices rest on the conveyor. All hangers, conveyors, etc. must be cleaned often to ensure a good ground and prevent anyone in the area from getting a severe shock. In an airborne system, any recesses on the piece that is being coated can be missed because the electrostatic paint is more attracted to corners and sharp edges; this means that another process for coating can be a better option if the piece has recesses. In the dipping process, air entrapment can occur in blind holes and deep recesses, so the positioning of the part as it enters the paint tank is critical in removing any trapped air that will restrict paint coverage.
Electrostatic-sensitive device
Often an ESD-safe foam or ESD-safe bag are required for transporting such components. When working with them, a technician will often use a grounding mat or other grounding tool to keep from damaging the equipment. A technician may also wear antistatic garments or an antistatic wrist strap
James Wimshurst
Wimshurst dedicated large amounts of his free time to experimental works. Besides his electrical activities, he invented a distinctive vacuum pump, a device to indicate ship stability and methods for electrically connecting lighthouses to the mainland. In 1878, he began to experiment with electrical influence machines for generating electrical sparks for scientific and entertainment purposes. Beginning in 1880, he became interested in electrostatic machines of the influence type. His house in Clapham, England, had a versatile workshop which had a wide variety of tools and devices for electric illumination. Wimshurst constructed several of the known types of electrostatic generators, such as those created by W. Nicholson, F. P. Carré and W. T. B. Holtz. To these predecessors, Wimshurst made many modifications with the result known as the Holtz-Wimshurst machine.
Stunning
The CrustaStun is a device designed to administer a lethal electric shock to shellfish (such as lobsters, crabs, and crayfish) before cooking. This avoids boiling a live shellfish which may be able to experience pain in a way similar to vertebrates. The device works by applying a 110 volt, 2–5 amp electrical charge to the animal. It is reported the CrustaStun renders the shellfish unconscious in 0.3 seconds and kills the animal in 5 to 10 seconds, compared to 3 minutes to kill a lobster by boiling or 4.5 minutes for a crab.
Electron gun
The most common use of electron guns is in cathode ray tubes, which were widely used in computer and television monitors. An electron gun can also be used to ionize particles by adding or removing electrons from an atom. This technology is sometimes used in mass spectrometry in a process called electron ionization to ionize vaporized or gaseous particles. More powerful electron guns are used for welding, metal coating, 3D metal printers, metal powder production and vacuum furnaces.
Electrostatic fluid accelerator
An electrostatic fluid accelerator (EFA) is a device which pumps a fluid such as air without any moving parts. Instead of using rotating blades, as in a conventional propeller or in the turbine of an airbreathing jet engine, an EFA uses the Coulomb force from a high voltage electric field to accelerate electrically charged air molecules, a phenomenon studied in the academic discipline called electrohydrodynamics (EHD). Because air molecules are normally neutrally charged, the EFA has to create some charged molecules, or ions, first. Thus there are three basic steps in the fluid acceleration process: ionize air molecules, accelerate those charge carriers and, through ion-ion and ion-neutral collisions, push many more neutral molecules in a desired direction, and finally neutralize ions again to eliminate any net charge in the downstream flow. This principle is used for spacecraft propulsion in ion thrusters.
Electrostatic pickup
The electrostatic pickup consists of a capacitor with one stationary plate and one moving plate. The moving plate is typically a steel or brass reed, anchored at one end and free to vibrate at the other end. Another fixed plate is suspended near the vibrating reed, but is electrically insulated.
A high voltage is applied between the stationary and moving plates to produce an electric field. The motion of the moving plate induces a varying current through the capacitor formed by the reed and the fixed plate.
Large electrostatic generator (Teylers)
The large electrostatic generator (Dutch: "Van Marum electriseermachine") is a large handcrafted electromechanical instrument designed by Martin van Marum and built by John Cuthbertson in 1784 for the Teylers Museum in Haarlem, where it forms the centerpiece of the instrument room. The concept of an electrostatic generator was new, and the battery (array) of leiden jars was the largest ever built (only one of the 4 sets of leiden jars is on display to conserve space). The two glass disks of the generator are 1.65 meters in diameter, and the machine is capable of generating a potential of 330,000 volts.
Electrostatic generator
Electrostatic machines are typically used in science classrooms to safely demonstrate electrical forces and high voltage phenomena. The elevated potential differences achieved have been also used for a variety of practical applications, such as operating X-ray tubes, medical applications, sterilization of food, and nuclear physics experiments. Electrostatic generators such as the Van de Graaff generator, and variations as the Pelletron, also find use in physics research.
Electrostatic loudspeaker
Musical transparency can be better than in electrodynamic speakers because the radiating surface has much less mass than most other drivers and is therefore far less capable of storing energy to be released later. For example, typical dynamic speaker drivers can have moving masses of tens or hundreds of grams whereas an electrostatic membrane only weighs a few milligrams, several times less than the very lightest of electrodynamic tweeters. The concomitant air load, often insignificant in dynamic speakers, is usually tens of grams because of the large coupling surface, thus contributing to the damping of resonance buildup by the air itself to a significant, though not complete, degree. Electrostatics can also be executed as full-range designs, lacking the usual crossover filters and enclosures that could color or distort the sound.
Electrostatic precipitator
Electrostatic precipitators can be used to sample biological airborne particles or aerosol for analysis. Sampling for bioaerosols requires precipitator designs optimised with a liquid counter electrode, which can be used to sample biological particles, e.g. viruses, directly into a small liquid volume to reduce unnecessary sample dilution. See Bioaerosols for more details.
Rotational bell painting
The electrostatic system can be internal or external (or direct or indirect charge), and supplies high voltage (30,000 to 100,000 volts DC) charge to the applicator, or the air surrounding it. This has the effect of negatively charging the paint, while causing a region of positive charge to form on the workpiece, resulting in electrostatic attraction between the paint and the workpiece. The electrostatic system is visible only on an external (or indirect) charge applicator, where it appears as a series of 4-8 forward-facing electrodes in a circular array around the bell. It is typically called a 'candelabra' for its resemblance to one.
Dust collector
Electrostatic precipitators use electrostatic forces to separate dust particles from exhaust gases. A number of high-voltage, direct-current discharge electrodes are placed between grounded collecting electrodes. The contaminated gases flow through the passage formed by the discharge and collecting electrodes. Electrostatic precipitators operate on the same principle as home "Ionic" air purifiers.
Electrohydraulic forming
Electrohydraulic forming (EHF) is based on the ultra-high-speed deformation of metal using shockwaves in water. Using the discharge of current from a capacitor bank, an electric arc is generated in water between two electrodes. This electric arc vaporizes the surrounding water, converting electrical energy into an intense shockwave of mechanical energy.
The shockwave simultaneously transforms the metal workpiece into a visco-plastic state and accelerates it into a die, enabling forming of complex shapes at high speeds in cold conditions. All of which happens in a matter of milliseconds; total cycle time of seconds including charging time of the system. This process is not limited by size and allows forming of parts up to a few square meters in size. An array of electrodes can be placed over a large workpiece, enabling pressure distribution according to the product’s topology, still using a one-sided die to create complex shapes and fine details.
Electrostatic voltmeter
The electrostatic voltmeter draws no significant current from the source when used on direct current, and a relatively small current due to the capacitance of the instrument when used with AC voltage. Instruments of this type were made with ranges of up to 100,000 volts full scale.
Electrostatic spray-assisted vapour deposition
The process has advantages over other techniques for layer deposition (Plasma, Electron-Beam) in that it does not require the use of any vacuum, electron beam or plasma so reduces the manufacturing costs. It also uses less power and raw materials making it more environmentally friendly. Also the use of the electrostatic field means that the process can coat complex 3D parts easily.
Fan (machine)
An electrostatic fluid accelerator propels airflow by inducing motion in airborne charged particles. A high voltage electric field (commonly 25,000 to 50,000 volts) formed between exposed charged anode and cathode surfaces is capable of inducing airflow through a principle referred to as ionic wind. The airflow pressure is typically very low but the air volume can be large. However, a sufficiently high voltage potential can also cause the formation of ozone and nitrogen oxides, which are reactive and irritating to mucous membranes.