What Is The Basic Electrical Knowledge?

Electricity is the flow of electrons through a conductor. Atoms are made up of protons, neutrons and electrons. Electrons can be made to flow from one atom to another with the application of tension and pressure. When the electrons flow from one place to another, electricity is created.

There are two main types of electricity – static electricity and current electricity. Static electricity refers to an imbalance of electric charges within or on the surface of material. This causes static cling or small shocks when you touch metal after walking across a carpet. Current electricity, on the other hand, refers to the steady flow of electrons through a conductor. This flow of electrons allows us to power appliances and transmit energy.

Electricity can also be either alternating current (AC) or direct current (DC). AC electricity flows back and forth in a circuit continuously reversing direction. The most common source is the electric power that comes from a wall outlet. DC electricity flows in only one direction. Batteries are common DC power sources.

In summary, electricity is the flow of electrons through a conductor. It can take the form of static charges or current flow. The current can alternate directions like AC power, or flow in one direction like DC power. This basic force allows us to power the modern world.

Table of Contents

Voltage, Current, and Resistance

Electricity is the flow of electric charge. There are three key concepts that are important to understand: voltage, current, and resistance.

Voltage is the difference in electric potential between two points in a circuit. It is measured in volts. Voltage is sometimes referred to as electric pressure, as it is the “push” that causes electricity to flow in a circuit.

Current is the rate at which electric charge flows past a point in a circuit. It is measured in amperes, or amps for short. Current is essentially the amount of electricity flowing through a wire or component.

Resistance is a measure of the opposition to current flow in a circuit. It is measured in ohms. Resistance limits the flow of electrons through a circuit.

These three concepts are related by Ohm’s law, which states that the current flowing between two points is directly proportional to the voltage across the two points, and inversely proportional to the resistance between them. This relationship is often stated as:

Voltage (V) = Current (I) x Resistance (R)

So in an electrical circuit, increasing voltage will cause current to increase, while increasing resistance will decrease current. Ohm’s law is a key tenet in understanding electrical circuits.

Series vs Parallel Circuits

Series and parallel circuits are the two fundamental ways in which electrical components can be connected. While both types of circuits power multiple components using the same voltage source, they function in very different ways.

In a series circuit, electrical components are connected end-to-end in a single loop. The current passes through each component in sequence before returning to the power source. Since the current has only one path to take, the current is the same through each component. The major advantage of series circuits is that the voltage drops across each component are additive. This allows for components with higher voltage requirements to be powered efficiently using lower voltage sources. However, since the current is constant throughout, the failure of a single component can break the entire circuit.

In a parallel circuit, electrical components are connected between two sets of wires, with separate paths for the current to flow. The voltage across each component is the same. However, the current splits across the different branches of the circuit. An advantage of parallel circuits is that each component can be supplied with the full source voltage. In addition, the failure of one component generally will not affect the function of the others. A disadvantage is that the total current draw can exceed the maximum that the source can provide. Parallel circuits require more complex analysis but allow for efficient power distribution.

To summarize, series circuits provide only one path for current but can efficiently increase voltage. Parallel circuits allow voltage to be consistent but require more complex current calculations. Knowing when to use each configuration is key to designing effective electrical systems.

Circuit Components

Electrical circuits are made up of various components that serve different functions. Some of the most common components include:

Resistors

Resistors are components that resist the flow of electric current. They are used to limit current flow and divide voltages in circuits. Resistors work by converting electrical energy into heat. They are rated by their resistance value in ohms.

Capacitors

Capacitors are components that store electric charge temporarily. They are used for filtering signals, blocking DC signals, and storing energy. Capacitors store energy by accumulating electrons on one plate and having fewer electrons on the other. They are rated by their capacitance value in farads.

Inductors

Inductors are components that store energy in a magnetic field. They are made of coiled wires and are used to block AC signals while allowing DC signals to pass. Inductors oppose changes in current by inducing a back EMF force. They are rated by their inductance value in henrys.

Transformers

Transformers are devices that increase or decrease AC voltages. They work through electromagnetic induction between two coils. Transformers isolate circuits and match impedances. They have a primary coil that receives energy and a secondary coil that transfers energy.

Measuring Electricity

When working with electricity, it’s important to be able to measure and quantify parameters like voltage, current, and resistance. Some key tools and techniques for measuring electricity include:

Multimeters – These versatile devices allow you to measure voltage, current, and resistance. Multimeters have different settings that allow you to configure them to measure the desired parameter. To measure voltage, connect the multimeter in parallel across the circuit component you want to measure. To measure current, connect the multimeter in series in the circuit path. Make sure to select the appropriate range on the multimeter dial for the expected voltage or current.

Clamp meters – These devices allow you to easily measure current flowing through a wire without having to break the circuit path. The wire is simply threaded through the jaws of the clamp meter. This is useful for measuring current in a live circuit. The clamp jaws contain a magnetic core which detects the magnetic field produced by current flowing through the wire.

Ohmmeters – These specialized devices measure resistance. Most digital multimeters have an ohmmeter setting that allows resistance measurement. Ohmmeters apply a small voltage to a component and measure the resulting current flow to determine resistance using Ohm’s Law (R = V/I).

Oscilloscopes – Oscilloscopes display a voltage waveform graphically on a screen, allowing you to visualize signals varying over time. They can measure voltage levels as well as frequency, period and other parameters of a waveform.

Using the right equipment and techniques allows you to quantitatively analyze and troubleshoot electrical circuits by taking measurements to determine voltage, current, resistance and other parameters.

Magnetism and Electromagnetism

Magnetism is a force that acts between magnets and certain materials like iron. It arises due to the motion of electrons in atoms. Electrons have an intrinsic magnetic dipole moment. Inside materials, the magnetic dipoles of individual atoms normally point in random directions, cancelling each other out. However in some materials like iron, the electron dipoles tend to align, producing a net magnetic field and creating a magnet.

When a magnet is brought near a magnetic material like iron, the dipoles in the material realign, causing the material to be attracted to the magnet. The force between a magnet and magnetic material is called magnetism. The closer the material, the stronger the force.

Electromagnetism describes the relationship between electricity and magnetism. An electric current in a wire gives rise to a magnetic field perpendicular to the direction of the current. Wrapping a wire into a coil concentrates the field, creating an electromagnet. The magnetic field disappears when the current stops.

The principles of electromagnetism are used in electrical equipment like motors, generators, and transformers. For example, in an AC generator, a rotating magnet causes electrons in a wire coil to flow back and forth, generating alternating current electricity. Motors work on the reverse principle, using a current-carrying coil in a magnetic field to produce rotation.

Electromagnets are used extensively, from lifting scrap metal to particle accelerators. An electromagnet can be quickly turned on and off by controlling the electric current. Its magnetic strength can also be varied by changing the amount of current flow. This allows precise control for applications like magnetic levitation trains and MRI machines.

Generators

Generators produce electricity through a process called electromagnetic induction. This process uses magnetism and movement to induce a voltage in a conductor like a wire. There are a few key principles that allow generators to work.

First, generators rely on the concept that moving a magnetic field around a conductor will induce a voltage in that conductor. This is known as Faraday’s Law of electromagnetic induction. A basic generator consists of a magnet surrounded by a coil of wire. When the magnet spins near the coil, the changing magnetic field induces a voltage in the coil.

Second, generators convert mechanical energy into electrical energy. The source of mechanical energy causes the magnet inside the generator to spin. Common sources are water turbines, wind turbines, engines powered by fuel, or even hand cranks. As the magnet spins, the magnetic field around the coils changes, inducing a voltage.

Third, the alternating current produced needs to be converted to direct current. The voltage induced alternates as the magnet spins, producing AC. A component called a commutator switches the connections to the coil to convert the current to DC.

Fourth, the voltage output needs to be increased to a usable level. Generators produce low voltages, so the electricity is run through step-up transformers to increase the voltage to 120 or 240V for the electrical grid.

In summary, generators produce electricity through electromagnetic induction by spinning a magnet near a coil of wire. The mechanical energy causes the magnet to spin, inducing an alternating voltage that is converted to direct current and stepped up to usable levels.

Motors

Electric motors convert electrical energy into mechanical energy to provide force or torque for movement. They work based on the principles of electromagnetism using magnetic fields caused by electric currents to exert a mechanical force that creates rotation. There are many types of electric motors with different operating principles and applications.

The most common type is the AC induction motor which consists of a rotating magnetic field that induces a current in the rotor. As the rotor’s magnetic field interacts with the stator’s rotating field, it spins the motor shaft. Induction motors are simple, rugged and efficient making them widely used in industrial machines, pumps, fans and household appliances. Another type is the DC motor which uses direct current to generate torque. The current in the armature windings interacts with the magnetic field from permanent magnets or electromagnets to create rotation. DC motors have good speed control and are commonly found in electric vehicles, cranes, and robotics.

Stepper motors divide a full rotation into steps allowing precise rotational positioning and control. They operate open-loop without requiring position sensors. Stepper motors are used in 3D printers, CNC machines and many other applications requiring accurate motion control. Brushless DC motors have a rotor with permanent magnets and electronic commutation instead of brushes. They provide high torque, efficiency and reliability with electronic speed control. Common uses include drones, computer fans, and electric bicycles.

Servo motors contain a position sensing device for precise speed and positional control in closed-loop applications. They are ideal for robotics requiring accurate positioning. Linear motors generate linear force along an axis instead of rotational torque. They are capable of high acceleration and speeds making them useful in maglev trains, conveyors, and machining applications.

Everyday Uses

Electricity powers the modern world and is something we all use constantly in our daily lives. Electricity allows us to illuminate our homes and workplaces with lighting, power communication devices like phones, computers and TVs, run appliances like refrigerators, microwaves and air conditioners, and operate machinery and equipment in homes, offices and factories. Some common examples of how we utilize electricity on a daily basis include:

– Lighting: From the simple lightbulbs in our home fixtures to fluorescent lights in offices to elaborate street lighting systems, electricity allows us to turn night into day and illuminate our environments.

– Cooking: Many modern cooking appliances like stoves, ovens, microwaves, toasters, electric kettles and slow cookers rely on electricity to quickly and conveniently cook our food.

– Refrigeration: Refrigerators and freezers use electricity to keep food and drinks chilled and fresh for longer durations.

– Heating/Cooling: Heating appliances like space heaters as well as cooling appliances like fans and air conditioners allow us to control temperatures and stay comfortable indoors.

– Entertainment: TVs, radios, games consoles, computers, mobile devices and more are powered by electricity, allowing us access to information, communication, news and entertainment.

– Cleaning: Vacuum cleaners, washing machines, dryers and dishwashers help automate cleaning tasks in our homes thanks to electricity.

– Transportation: Electric trains, trams, subways and increasingly cars rely on electricity to efficiently move people and goods.

Electricity has become indispensable in powering devices, appliances and equipment that increase productivity, improve quality of life and enable modern technological advances.

Electrical Safety

Working with electricity always comes with some level of risk, so it’s important to take proper precautions to avoid electric shock and other hazards. Here are some key tips for staying safe when working with electrical systems: