Electricity Windmill Explained


Electricity Windmill

Electricity windmill converts wind energy into electrical power via rotor blades, generator, gearbox, and inverter, supporting renewable energy, grid integration, power electronics, and efficient electricity production with modern control systems and variable-speed drives.

 

Electricity Windmill Fundamentals

Electricity windmill Mankind been harnessing the wind's energy for many years. From Holland to traditional farms around the world, old style windmills were used in the past for pumping water through primative irrigation systems or used to grind grain. Then, the wind turned large "sails" which were connected by a long vertical shaft that was attached to a grindnig machine or to a wheel that turned and drew water from a well. Today's wind turbine generators can utilize the clean energy of high wind speeds to turn large metal blades which in turn spins a generator that manufactures electric power. For a deeper overview of modern designs, the resource at windmills for electricity explains key configurations used by utilities today.

Electricity windmill turbines, unlike the machines of old, are mounted on very tall towers in order to capture the most wind energy available. At 100 feet (30 meters) or more above ground, wind turbines can take advantage of the faster and less turbulent wind. Turbines catch the wind's energy with their propeller-like blades. Usually, two or three blades are mounted on a shaft to form a rotor. If you're curious how these rotating blades ultimately power homes, see how turbines generate electricity through step-by-step conversion processes.

A blade acts much like an airplane wing. When the wind blows, a pocket of low-pressure air forms on the downwind side of the blade. The low-pressure air pocket then pulls the blade toward it, causing the rotor to turn. This is called lift. The force of the lift is actually much stronger than the wind's force against the front side of the blade, which is called drag. The combination of lift and drag causes the rotor to spin like a propeller, and the turning shaft spins a generator to make power. The rotating shaft must be matched to an electricity generator with appropriate gearing and controls to optimize output.

In recent years, governments have invested enormous amounts of (taxpayer) money in electricity windmill "wind farms" to generate large amounts of energy from large and small wind turbines that take advantage of high winds. These wind systems or energy systems use wind turbine power to create electricity.  Other energy sources like solar power do not produce as much electricity. The only problem with wind generated power is that when the wind stops, so does the generator and therefore the electric power production. Electric power cannot be produced and stored for consumption later. Therefore, wind power can only be counted on mostly when the wind is blowing at optimal speeds and only in locations where the prevailing winds are such that it makes economic sense to build these power plants and this may not be when and where the power is needed. Grid planners track regional electricity production profiles to determine how much wind capacity can be integrated without compromising reliability. As part of a balanced portfolio, policy makers also evaluate alternative electricity options that can complement variable wind resources.

Stand-alone electricity windmill turbines are typically used for water pumping or communications. However, homeowners, farmers, and ranchers in windy areas can also use wind turbines as a way to cut their power bills. For off-grid ranch operations, understanding the interplay between pumps and water electricity systems helps size batteries and controllers correctly.

Small electricity windmill systems also have potential as distributed energy resources. Distributed energy resources refer to a variety of small, modular power-generating technologies that can be combined to improve the operation of the electric power delivery system. In some regions, small-scale hydroelectricity can serve as a firm companion to wind in distributed portfolios.

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Hydroelectricity Explained

Hydroelectricity converts hydropower into grid-ready electricity using dams, penstocks, turbines, and generators, enabling renewable baseload, pumped storage, high efficiency, and low emissions for resilient power systems with load balancing, frequency regulation, and strong capacity factors.

 

Understanding How Hydroelectricity Works

Hydroelectricity is another term for power generated by harnessing the power of damming rivers and moving water into generating plants. Not necessarily falling water, just moving water. There are many famous such Hydroelectricity stations in the world, not the least of them at Niagara Falls, Grand Coulee and Boulder Dam and the three gorges dam in China . In the past, small plants produced electric hydroelectricity. Now, they are massive in size and generation capcity as well as having large reservoirs. If there is a need for power electrical generation stations situated close to the point of consumption is ideal. These are just a few of the many examples of energy produced by falling water. On the other hand, a small mill set in the rapids of a fast-moving stream is also an example of it in action, on a lesser scale. The truth is that any steady current of flowing water from a river or other waterway can be converted to power. Of all the sources electricity from hydroelectricity, dammed reservoirs is one of the cleanest possibe ways to generate electricity to a million people, compared with nuclear power. For broader background on water safety and power concepts, the guide on water and electricity explains interactions, risks, and basic generation principles.

 

How is HydroElectricity Generated?

Hydroelectricity is generated or "manufactured" in large hydroelectric plants, (electrical generating stations) using the same basic principle as a small grist mill yet on a much larger and vastly improved scale for better efficiency, using pumped storage. These power plants contain electrical generators which are attached to massive turbine devices which spin at great speeds as a result of water rushing through them. These pump water power station turbines are much more efficient at extracting the kinetic energy from the moving water and converting that energy it into electrical production through these generators. To see how hydro fits within the wider energy landscape, review how electricity is generated across different prime movers and grid systems.

The amount of electricity from Hydroelectricity extracted from water as an energy source depends not only on the capacities of volume sent through a hydroelectric power plant but on the difference in height between the source and the water's outflow. This height difference is called the head. The amount of potential energy in water is directly proportional to the head and how much water is released. To obtain very high head, water for a hydraulic turbine may be run through a large pipe called a penstock. These relationships between flow, head, and output are core electricity generation principles that guide plant design and optimization.

For instance, energy is derived to make electricity water has to move from a higher elevation to a lower elevation through a large tube" otherwise known in technical terms as a "penstock". When the water reaches the end of the penstock, it turns a water wheel or "turbine" at enormous speeds. The turbine rotates, via a connected shaft to an electrical generator, and this generator creates electricity. It is the turbine and generator working in combination that converts "mechanical energy" into "electric energy". The water that makes this possible, is a renewable energy resource, just like the wind that turns the turbine attached to a generator. This mechanical-to-electrical conversion is a classic way to generate electricity efficiently when hydraulic conditions are favorable.

Hydroelectricity may be extracted from water but it depends not only on the volume of water but also on the difference in height between the top of the penstock and where the water spins the turbine. This difference in height is often referred to as the "head". From this "head", it can be determined the exact amount of potential energy that can be converted. Therefore, it is advantageous to build power dams as high as possible to convert the maximum energy from mechanical energy. Project planners evaluate head, flow duration, and dispatch needs in the context of overall electricity production targets and grid reliability.

While many hydroelectricity generating stations supply world power grids, some projects are created for private business purposes. For example, aluminium manufacturing companies require large amounts of power. And there are many other examples of industries that use hydroelectricity in their manufacturing operations. Industrial facilities often diversify procurement among various sources of electricity to balance costs, resilience, and sustainability goals.

While hydroelectricity in the United States seems relatively clean and safe in comparison to burning fossil fuels (coal or oil or natural gas), nearly all large hydroelectricity installations in North America have significant had impacts on nearby environmental habitats once they are brought online. This is because they significantly impede the flow of water in rivers and lakes at the point where the generating dam is installed In turn, this causes significant increases in water levels in corresponding upstream water systems while at the same time creating much lower water levels downstream. Mitigation strategies may include fish passages, adaptive flow management, and complementary alternative electricity options to reduce ecological disruption.

 

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Electricity Supplier - Make The Right Choice

Electricity supplier delivers power via transmission and distribution networks, managing tariffs, load forecasting, SCADA, and power quality, integrating renewables, smart meters, and demand response to ensure grid reliability, compliance, and efficient kWh billing.

 

Understanding How an Electricity Supplier Works

Who is my electricity supplier?

In Canada and the United States, it’s easy to learn which energy provider serves your property or residence. It depends on whether you are trying to find your electricity and natural gas supplier. Sometimes, homes and businesses have the power to choose their energy service utility company and the products and service they provide. Customers are free to choose. It's a competitive energy marketplace. For a plain-language primer on infrastructure, see the electricity supply overview to understand typical delivery steps.

If you use both services, your property might have the same local distribution company for both fuels, – commonly known as a "duel fuel supplier". But if your utility records are stored separately, you might need to more research to learn who supplies your natural gas services and your electricity services separately. If you are curious where the power originates, this guide to how electricity is generated explains common fuel sources and grid integration.

 

Here is a list of accredited Electricity Suppliers in Canada

https://www.ic.gc.ca/eic/site/mc-mc.nsf/eng/lm00525.html

Market dynamics can vary by province, and recent electricity demand trends in Canada help explain seasonal shifts in offers.

 

Here is a list of accredited Electricity Suppliers in the United States.

https://www.electricchoice.com/blog/25-top-providers-part-1/

When comparing providers, consult current electricity price benchmarks to contextualize quoted rates.

 

Who can supply electricity?

All electricity supplier companies must have a licence from the Office of Gas and Electricity Markets (Ofgem). One of the licence conditions is that a  company must produce codes of practice on:

Although the codes of practice are not legally enforceable, they will be useful when negotiating with a company and any breach should be reported to governmental regulatory authorities. Understanding the basics in this introduction to what electricity is can make those obligations clearer.

 

Choosing an electricity supplier

You can change your company if you wish. If you are considering changing your company you should be aware that the pricing structures, services offered and policies will differ between the different companies.You should carefully check the information and contracts of the competing electricity suppliers, and compare these to your current terms, to make sure that you choose the best deal for your needs. A lot depends on your gas bills or electricity bill, and your location by postal code. You can also estimate bill impacts by applying tips from this guide on how to save electricity while comparing plans.

 

Dual fuel offers

Dual fuel is the supply of gas and electricity by the same company. Some gas and electricity suppliers are licensed separately by Ofgem to supply customers with both fuels. Some companies will supply both fuels under one contract, while others will give one contract for gas and another for electricity. For households with high usage, reviewing your typical electricity power consumption patterns can reveal whether dual fuel makes financial sense.

Electricity Suppliers who make dual offers will often give a discount off the total bill as they can make administrative savings by issuing combined bills and collecting combined payments. However, this does not necessarily mean that the cost of gas and electricity

  • procedures for complaints
  • payment of bills, arrangements for dealing with arrears and prepayment meters
  • site access procedures
  • energy efficiency advice
  • services for older, disabled and chronically sick people. As part of this code of practice, the company must keep a register of these people and provide services to help those who are blind and partially sighted or deaf or hearing impaired. Especially during a power outage, it is important that these customers are restored asap.The customer may have to pay for some of these services.
    • how you will be charged for your electricity supply. Some companies may make a fixed standing charge and then a unit charge for the amount of electricity used; an company may not make a standing charge, but charge a higher unit price
    • whether different charges apply to different periods during the day
    • if cheaper prices are offered for particular payment methods, for example, if you pay by direct debit
    • what service standards each company is offering, for example, for repairs, extra help for older or disabled customers.All electricity suppliers must keep a list of their customers who ask to be identified as pensioners, chronically sick or disabled.The electricity supplier must tell all its customers that it keeps such a list and give information on how customers can be added to the list
    • the company's policies, for example, on debt and disconnection.

 

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Wattmeters – Power Measurement

Wattmeters measure electrical power in watts, monitoring energy use in industrial power systems. They provide accurate active power readings for efficiency and load management, utilizing voltage and current measurements to achieve precise results.

 

What are Wattmeters?

Wattmeters are instruments used to measure electrical power. They:

✅ Measure active electrical power in watts for various applications.

✅ Are used in industrial, commercial, and residential energy monitoring.

✅ Help optimize efficiency, manage loads, and ensure system safety.

A wattmeter measures instantaneous (or short-term) electrical power in watts, while a watthour meter accumulates that power over time and reports energy used (e.g. in kWh). Energy meters and smart meters extend this concept by recording consumption continuously for billing, load analysis, and energy audits.

 

Working Principle of Wattmeters

Electrical power is calculated using the formula:

P = E × I

Where:

  • P = Power in watts

  • E = Voltage in volts

  • I = Current in amperes

In DC circuits, watts are sometimes expressed as volt-amperes (VA). In AC circuits, wattmeters measure true (or active) power, taking into account the power factor to compensate for phase differences between voltage and current. Unlike reactive power (measured in kvar) or apparent power (measured in kVA), active power is the usable portion that does real work. This relationship is often represented in the power triangle, where vector analysis explains how apparent, reactive, and active power interact.

 

Construction and Internal Components

A typical wattmeter consists of two main coil assemblies:

  1. Current Coil (CC)

    • Heavy-gauge copper wire with low resistance.

    • Connected in series with the load to carry the circuit current.

  2. Voltage Coil (VC)

    • Fine-gauge wire with high resistance.

    • Connected in parallel with the load to measure voltage.

The electrodynamometer, commonly referred to as a dynamometer wattmeter, is a classic analog device that operates on the principle of a motor. The interaction between the magnetic fields of the current and voltage coils produces a torque proportional to the power, causing the pointer to move over a calibrated scale. Understanding wattmeter principles is a foundation of basic electricity training, helping learners connect theory to practical power measurement.

 


 

Figure 1 – Construction of a dynamometer wattmeter showing current and voltage coil arrangement.

 

Types of Wattmeters

  • Analog/Dynamometer – Durable, reliable, suited for laboratory and field measurements.

  • Digital – Higher accuracy, data logging, and integration with monitoring systems.

  • Clamp-on  – Measure power without breaking the circuit, ideal for quick diagnostics.

  • Specialized  – Designed for RF power, audio power, or other niche applications.

In three-phase systems, wattmeters are often applied in accordance with Blondel’s theorem, which specifies the number of measurement elements required in multi-phase circuits. They are frequently used in conjunction with 3 phase electricity concepts to ensure balanced load distribution and optimal system efficiency.


 

Fig. 2. Power can be measured with a voltmeter and an ammeter.

 

Measuring Power in DC and AC Circuits

In DC circuits, power measurement can be as simple as multiplying voltage and current readings from separate meters.

Example:

If a circuit operates at 117 V DC and draws 1 A, the power is:

P = 117 × 1 = 117 W

In AC systems, especially with reactive or distorted loads, a wattmeter is essential because voltage and current may not be in phase. The device automatically accounts for the phase angle, providing accurate true power readings. Advanced digital wattmeters also compensate for harmonic distortion and poor waveform quality, providing more reliable measurements than older analog designs.

By measuring energy transfer in circuits, they also relate to other power measurement instruments such as ammeters, voltmeters, and multimeters, which measure supporting parameters needed for complete electrical analysis. Accurate wattmeter readings are crucial for diagnosing performance issues in 3-phase power networks, where the relationships between voltage and current are critical. By measuring energy transfer in circuits, they help explain fundamental laws of electromagnetism, such as Ampère’s Law, which underpins the interaction between current and magnetic fields.

 

Fig. 2. Power can be measured with a voltmeter and an ammeter.

 

Practical Examples and Load Considerations

A household iron may consume 1000 W, drawing 8.55 A at 117 V.

A large heater may draw 2000 W, or 17.1 A, potentially overloading a 15 A breaker.

In industrial settings, watt meters help prevent equipment overloading, reduce downtime, and improve energy efficiency.

 

Modern Wattmeter Applications

Today’s wattmeters are often part of smart energy monitoring systems that:

  • Track energy consumption over time.

  • Integrate with SCADA and IoT platforms.

  • Enable predictive maintenance through power trend analysis.

  • Support compliance with energy efficiency regulations.

 

Accuracy, Standards, and Advanced Considerations

Measurement accuracy is a crucial factor in determining wattmeter performance. Devices are often classified by a class of accuracy, with error limits defined by international standards such as IEC, ANSI, or IEEE. Regular calibration and testing procedures ensure watt meters continue to deliver reliable results in both laboratory and field conditions.

Modern digital watt meters feature true RMS measurement, which accurately captures distorted waveforms caused by nonlinear loads. This is especially important in power systems where harmonic distortion is present. In commercial and industrial environments, accurate wattmeter data support energy audits, load analysis, and regulatory compliance, making them indispensable tools for engineers and facility managers. Wattmeter usage is closely linked to the fundamentals of electrical energy, enabling precise monitoring for efficiency and cost control.

 

Key Advantages of Wattmeters

  • Accurate real-time power measurement.

  • Enhanced energy management and cost savings.

  • Improved system reliability through overload prevention.

  • Compatibility with both AC and DC systems.

Wattmeters remain a vital tool for measuring and managing electrical power. Whether in a simple residential circuit, a commercial energy audit, or a high-tech industrial monitoring system, they ensure that electrical systems run efficiently, safely, and cost-effectively. As technology advances, digital and networked wattmeters continue to expand their role, integrating into smart grids and energy-optimized infrastructures. 

 

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Water Electricity

Water electricity refers to electrical power generated using water, primarily through hydroelectric systems. It converts the kinetic energy of moving or falling water into electricity, providing a renewable and sustainable energy source with low carbon emissions and high efficiency.

 

What is: “Water Electricity?”

Water electricity, also known as hydroelectric power, is energy derived from moving water. It’s a leading source of renewable electricity worldwide.

✅ Converts water’s kinetic energy into usable electricity

✅ Offers renewable, low-emission electricity generation

✅ Used in dams, rivers, and tidal energy systems

 Most hydroelectric power is generated from the potential energy of dammed water, which drives a water turbine and generator. Less common variations utilize water's kinetic energy or undammed sources, such as tidal power. Hydroelectricity is a renewable energy source.

The energy extracted from water depends not only on the volume but on the difference in height between the source and the water's outflow. This height difference is referred to as the head. The amount of potential energy in water is directly proportional to the head. To obtain a very high head of water for a hydraulic turbine, water may be run through a large pipe called a penstock.

While many supply public power networks, some Water Electricity projects were created for private commercial purposes. For example, aluminum processing requires substantial amounts of power, and in Britain's Scottish Highlands, there are examples at Kinlochleven and Lochaber, designed and constructed during the early 20th century. Similarly, the 'van Blommestein' lake, dam and power station were constructed in Suriname to provide power for the Alcoa aluminum industry. In many parts of Canada (specifically, the provinces of British Columbia, Manitoba, Ontario, Quebec, and Newfoundland and Labrador), hydroelectricity is used so extensively that the word "hydro" is often used to refer to any power delivered by a power utility. The government-run power utilities in these provinces are called BC Hydro, Manitoba Hydro, Hydro One (formerly "Ontario Hydro"), Hydro-Québec and Newfoundland and Labrador Hydro, respectively. Hydro-Québec is the world's largest hydroelectric generating company, with a total installed capacity (2005) of 31,512 MW. For deeper insight into how to generate electricity from various sources, including water, visit our guide on hydroelectricity, which explains methods, systems, and real-world examples.

 

Importance

Water and Electricity power supplies 20% of the world's electricity. Norway produces virtually all of its energy from hydroelectric sources. In contrast, Iceland produces 83% of its requirements (as of 2004), and Austria generates 67% of all power in the country from hydroelectric sources (over 70% of its total requirements). Canada is the world's largest producer of Water Electricity, and produces over 70% of its electric power from hydroelectric sources.

Apart from a few countries with an abundance of it, hydro capacity is normally applied to peak-load demand, because it can be readily stored during off-peak hours (in fact, pumped-storage hydroelectric reservoirs are sometimes used to store power produced by thermal plants for use during peak hours). It is not a major option for the future in developed countries because most major sites in these countries that have the potential for harnessing gravity in this way are either already being exploited or are unavailable for other reasons, such as environmental considerations.

Regions where thermal plants provide the dominant supply of power utilize Water Electricity to provide the important functions of load following and regulation. This permits thermal plants to be operated closer to thermodynamically optimal points rather than varied continuously, which reduces efficiency and potentially increases pollutant emissions. Concurrently, hydro plants are then utilized to provide for hour-to-hour adjustments and to respond to changes in system frequency and voltage (regulation), with no additional economic or environmental effect.

 

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Electrical Resistance Definition Explained

Electrical resistance definition explains how materials oppose current flow in circuits, measured in ohms, linked to voltage, resistivity, conductor geometry, temperature, and impedance, governed by Ohm's law and SI units in electronics.

 

Quick Reference: Electrical Resistance Definition

Electrical Resistance Definition: ER occurs in an electrical circuit when current-carrying charged particles collide with fixed particles that make up the structure of the conductors. Resistance is measured in ohm. Resistance is the ohm w. Resistance occurs in every part of a circuit, including wires and especially power transmission lines. For a concise overview, see this introduction to electrical resistance to reinforce key definitions.

Dissipation of electric energy in the form of heat affects the amount of driving voltage required to produce a given current through the circuit. In fact, volts are mesured across a circuit divided by the current I (amperes) through that circuit defines quantitatively the amount of electrical resistance R. The ohm is the common unit of electrical resistance, equivalent to one volt per ampere and represented by the capital Greek letter omega, Ω. The electrical resistance of a wire is directly proportional to its length and inversely proportional to its cross-sectional area. Resistance also depends on the material of the conductor. For instance, the resistance of a conductor generally increases with increasing temperature the resistivity. This is why some conductors have almost zero resistance when cooled to extremely low temperatures, as is the case with superconductors, because of the relative resistivity of metals. There is a temperature coefficient of resistivity. If you need a refresher on potential difference and its role in circuits, review this explanation of voltage to connect the concepts.

Alternating-current resistors for current measurement require further design consideration. For example, if the resistor is to be used for current-transformer calibration, its ac resistance must be identical with its dc resistance within 1/100th% or better, and the applied voltage difference between its voltage terminals must be in phase with the current through it within a few tenths of a minute. Thin strips or tubes of resistance material are used to limit eddy currents and minimize "skin" effect, the current circuit must be arranged to have small self-inductance, and the leads from the voltage taps to the potential terminals should be arranged so that, as nearly as possible, the mutual inductance between the voltage and current circuits opposes and cancels the effect of the self-inductance of the current circuit. In (a) a metal strip has been folded into a very narrow U; in (b) the current circuit consists of coaxial tubes soldered together at one end to terminal blocks at the other end; in (c) a straight tube is used as the current circuit, and the potential leads are snugly fitting coaxial tubes soldered to the resistor tube at the desired separation and terminating at the center. These design choices are also easier to contextualize by comparing common types of resistors used for precise AC measurements.

Electrical Resistance coils consist of insulated resistance copper wire wound on a bobbin or winding form, hard-soldered at the ends to copper terminal wires. Metal tubes are widely used as winding form for dc resistors because they dissipate heat more readily than insulating bobbins, but if the resistor is to be used in ac measurements, a ceramic winding form is greatly to be preferred because it contributes less to the phase-defect angle of the resistor. The resistance wire ordinarily is folded into a narrow loop and wound bifilar onto the form to minimize inductance. This construction results in considerable associated capacitance of high-resistance coils, for which the wire is quite long, and an alternative construction is to wind the coil inductively on a thin mica or plastic card. The capacitive effect is greatly reduced, and the inductance is still quite small if the card is thin. When specifying coil assemblies, it helps to recall the standardized unit of electrical resistance so ratings and tolerances are interpreted consistently.

Resistors in which the wire forms the warp of a woven ribbon have lower time constants than either the simple bifilar- or card-wound types. Manganin is the resistance material most generally employed, but Evanohm and similar alloys are beginning to be extensively used for very high resistance coils. Enamel or silk is used to insulate the wire, and the finished coil is ordinarily coated with shellac or varnish to protect the wire from the atmosphere. Such coatings do not completely exclude moisture, and dimensional changes of insulation with humidity will result in small resistance changes, particularly in high resistances where fine wire is used. Material behavior, moisture effects, and long term stability are discussed further in this broader overview of electrical resistance for additional context.

Electrical Resistance boxes usually have two to four decades of resistance so that with reasonable precision they cover a considerable range of resistance, adjustable in small steps. For convenience of connection, terminals of the individual resistors are brought to copper blocks or studs, which are connected into the circuit by means of plugs or of dial switches using rotary laminated brushes; clean, well-fitted plugs probably have lower resistance than dial switches but are much less convenient to use. The residual inductance of decade groups of coils due to switch wiring, and the capacitance of connected but inactive coils, will probably exceed the residuals of the coils themselves, and it is to be expected that the time constant of an assembly of coils in a decade box will be considerably greater than that of the individual coils. Understanding how series and parallel combinations set the equivalent resistance will inform how decade boxes are deployed in complex networks.

Measurement of resistance is accomplished by a variety of methods, depending on the magnitude of the resistor and the accuracy required. Over the range from a few ohms to a megohm or more, an ohmmeter may be used for an accuracy of a few percent. A simple ohmmeter may consist of a milliammeter, dry cell, and resistor in a series circuit, the instrument scale being marked in resistance units, if you obey ohm law. For a better value, the voltage drop is measured across the resistor for a measured or known current through it. Here, accuracy is limited by the instrument scales unless a potentiometer is used for the current and voltage measurements. The approach is also taken in the wide variety of digital multimeters now in common use. Their manufacturers' specifications indicate a range of accuracies from a few percent to 10 ppm (0.001%) or better from the simplest to the most precise meters. Bridge methods can have the highest accuracy, both because they are null methods in which two or more ratios can be brought to equality and because the measurements can be made by comparison with accurately known standards. For two-terminal resistors, a Wheatstone bridge can be used; for four-terminal measurements, a Kelvin bridge or a current comparator bridge can be used. Bridges for either two- or four-terminal measurements also may be based on resistive dividers. Because of their extremely high input impedance, digital voltmeters that be used with standard resistors in unbalanced bridge circuits of high accuracy. For quick reference during test planning, the fundamental resistance formula clarifies how R, V, and I are related under Ohm law.

Digital multi meters are frequently used to make low-power measurements of resistors in the range between a few ohms and a hundred megohms or so. Resolution of such instruments varies from 1% of full scale to a part per million of full scale. These meters generally use a constant-current source with a known current controlled by comparing the voltage drop on an internal "standard" resistor to the EMF produced by a Zener diode. The current is set at such a level as to make the meter direct-reading in terms of the displayed voltage; that is, the number displayed by the meter reflects the voltage drop across the resistor, but the decimal point is moved and the scale descriptor is displayed as appropriate. Multimeters typically use three or more fixed currents and several voltage ranges to produce seven or more decade ranges with the full-scale reading from 1.4 to 3.9 times the range. For example, on the 1000-0 range, full scale may be 3,999.999 Q. Power dissipated in the measured resistor generally does not exceed 30 mW and reaches that level only in the lowest ranges where resistors are usually designed to handle many times that power. The most accurate multimeters have a resolution of 1 to 10 ppm of range on all ranges above the 10-0 range. Their sensitivity, linearity, and short-term stability make it possible to compare nominally equal resistors by substitution with an uncertainty 2 to 3 times the least count of the meter. This permits their use in making very accurate measurements, up to 10 ppm, or resistors whose values are close to those of standards at hand. Many less expensive multimeters have only two leads or terminals to use to make measurements. In those cases, the leads from the meter to the resistor to be measured become part of the measured

 

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Static Electricity

Static electricity is a fascinating phenomenon that can be both awe-inspiring and dangerous. Understanding its basic concepts, including the movement of charged particles and the causes of positive and negative charge imbalance, is crucial in preventing potential hazards. By taking preventive measures such as grounding equipment and surfaces, using anti-static materials, and increasing humidity, we can avoid the buildup of static charges and protect ourselves and our environment from its hazards. It is also important to understand the potential dangers and take appropriate precautions, particularly when working with flammable or explosive materials. With this knowledge, we can safely harness the power and explore its many fascinating properties.


What is static electricity?

It results from the movement of charged particles, called electrons and particles called protons, which make up the atoms of matter. Atoms are made up of protons, neutrons, and electrons. Protons have a positive charge, electrons have a negative charge, and neutrons have no charge. In most atoms, the positive charge of the protons is balanced by the negative charge of the electrons, resulting in a neutral object.

However, when two objects come in contact, the extra electrons from one object may transfer to the other, creating a charge imbalance. This results in one object having a positive charge and the other having a negative electric charge. These charges repel, and when the objects are separated, they retain the charges, creating a static charge.


What causes static electricity?

As previously mentioned, it is caused by the movement of charged particles. When there is a charge imbalance between two objects, it can create a static charge. This can occur through friction, conduction, or induction.

Friction occurs when two objects rub against each other, causing electrons to transfer from one object to the other. For example, this is why you may experience it when you rub a balloon against your hair, causing your hair stand to stand up.

Conduction occurs when two objects come in contact and transfer electrons between them. For example, when you touch a doorknob, you may receive a static shock if the doorknob is charged.

Induction occurs when a charged object is brought near a neutral object, causing a charge to be induced in the neutral object.


How does static electricity work?

It creates a charge imbalance between two objects, resulting in one object having a positive charge and the other having a negative charge. These charges repel each other, and when the objects are separated, they retain the charges, creating a static charge.

When a charged object comes in contact with a neutral object, the charge may transfer, resulting in a static shock. This occurs when the charge imbalance is released as a spark. Static shocks are usually harmless but can sometimes be dangerous, particularly in hazardous environments.


Can static electricity hurt you?

While it is usually harmless, it can sometimes be dangerous. A static shock occurs when a charged object comes in contact with a person or object that is not charged. The shock results from the charge imbalance being released as a spark. The shock can be uncomfortable, and in rare cases, it can cause serious injury, mainly if it occurs in a hazardous environment, such as around flammable materials.


What are the dangers of static electricity?

It can be dangerous in certain situations, such as when working with flammable or explosive materials. A spark from it can ignite flammable gases or vapours, leading to fires or explosions. In industrial settings, it is important to take precautions to prevent the buildup of static charges and to discharge any charges that may occur.


How do you discharge static electricity?

There are several ways to discharge it, including:

  • Grounding: Connecting the charged object to a ground source such as the earth, which dissipates the excess charge.
  • Anti-static materials: Wearing clothes made of anti-static materials or using anti-static sprays can prevent the buildup of static charges.
  • Humidification: Increasing the humidity in a room can help reduce a buildup by adding moisture to the air.
  • Use of ionizers: Ionizers can neutralize it by releasing negative ions into the air.
  • Proper grounding of equipment: Ensuring that all equipment and surfaces are properly grounded can prevent the buildup of static charges.


How can you prevent static electricity?

Preventing buildup involves taking several steps, such as:

  • Using anti-static materials: Clothing made of anti-static materials or anti-static sprays can prevent the buildup of static charges.
  • Grounding: Ensuring that all equipment and surfaces are properly grounded can prevent the buildup of static charges.
  • Humidification: Increasing the humidity in a room can help reduce a buildup by adding moisture to the air.
  • Proper handling of flammable materials: When working with flammable or explosive materials, it is important to take proper precautions to prevent a buildup and discharge of any charges.
  • Using equipment designed for use in hazardous environments: Equipment designed for use in hazardous environments is designed to prevent a buildup and sparks from occurring.

In addition to these preventive measures, it is important to understand the basics of static electricity and the factors that contribute to its buildup. This knowledge can help individuals take steps to avoid buildup and prevent any potential hazards.

 

Van de Graaff Generator: An Experiment with Static Electricity

One fascinating example of this is the Van de Graaff generator. This device was invented in 1929 by Robert J. Van de Graaff and is used to generate high voltages of static electricity. The generator transfers electrons from a moving belt to a metal sphere, creating a charge imbalance between the two objects.

This charge imbalance creates a strong electric field, which can be used to demonstrate various phenomena. For example, the electric field can cause hairs on a person's head or arm to stand up due to the repulsion between the positively charged hair and the positively charged metal sphere.


 

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