Author: Abdul Wahab

Today batteries are very common devices in every portable electronic device. You smartphones contain a battery so that you can use your smartphone without being connected to the power socket all the time. Batteries are used in the vehicles for self-starting and running electronics smoothly.

What are the Batteries?

Batteries are electronic devices which can store the electrical energy so that it can be used when needed. They are two terminals in every kind of battery which provide the electricity when these terminals are connected to load, such as LEDs in the flashlight. One terminal is called positive (+) and the other is called negative (-). The electric current, also called conventional current, continues from positive terminal towards negative terminal.

Batteries come in a wide variety of storage capacities, sizes, and shapes. For example, smartphones mostly contain rectangular shaped batteries – smaller in size than the smartphone itself. The batteries can be connected together in series or parallel circuit configuration to increase the overall voltages or battery capacity.

If the terms voltage, current, or circuit configurations are confusing you, consider reading about them from the electricity section on our website.

Difference between Batteries and Cells

You often hear the words cells and batteries as electrical storage devices. Many people consider the cells and batteries as same things. They are actually different but both of them store the electrical energy. Cells are the basic units which when combined together form a battery. Batteries are made by combining several cells together for increasing the voltage, capacity, or both.

How Batteries Work

All types of batteries available in the market for purchase store the electricity in form chemical energy. When the electricity is needed back from the battery, a chemical reaction happens that generate the electricity and supplies it loads.

The chemical reaction happens between the anode (+ terminal) and cathode (- terminal) inside a battery. The reaction is called redox (reduction and oxidation) reaction which happens through an electrolyte – a liquid that contains ions (free moving charges). The reaction starts when two terminal – positive and negative – are connected together through a wire or load.

Types of Batteries

There are many types of batteries which are all categorized into two broad categories. These are primary and secondary batteries.

• Primary Batteries – These types of batteries are not rechargeable and are replaced with new ones when they are completely discharged. The batteries in most toys and remote controls are primary batteries because we through them to recycle bins when they are dead. Primary batteries are not able to recharge because the chemical that happens inside the battery is irreversible. Some of the examples of these batteries are alkaline batteries and zinc-carbon batteries.
• Secondary Batteries – These are rechargeable batteries and doesn’t need to be replaced once they are discharged – only recharge them. You can find these batteries in smartphones, vehicles, and power backup devices. Secondary batteries are made with materials whose reaction is reversible – means they can return to original form when you supply them with electricity from a charger. The examples of these types of batteries are Lead acid batteries and Li-ion Batteries.

Facts

• Nuclear batteries are the type of batteries that don’t run on a chemical reaction but on a nuclear reaction.
• Batteries generate direct current (DC) that flow in only one direction. The current in your power sockets is alternating current (AC) which changes direction with a certain frequency (e.g. 50 or 60 Hertz).
• The invention of batteries happened before the invention of electric generators, and scientists have to rely on electric power from batteries for experiments.

Electric motors are one of the most common electrical machines that can be found in a wide range of electronic devices. You will find several items in the home which contain motors in it, such as fans, grinders, mixer, moving toys, and vacuum cleaners.

What Are Electric Motors?

Electric motors are the electrical machines that work on electricity to produce mechanical power. Mechanical power can be used to rotate the fans or move an electric car etc. Electrical motors come is many voltage and power ratings, for example, 120 volts, 220 volts, and 12 volts. They need to be supplied with their rated voltage to ensure the smooth operation and avoid damages.

How Electric Motors Works?

The basic principle behind the working of an electric motor is the action of electromagnetic forces. When a wire carries an electric current and is placed in a magnetic field (e.g. near a magnet), it feels a force that pushes it in a certain direction – depending on the orientation of wire and magnetic poles.

The body of a motor is made of two main parts; static part and rotating part. The static part contains a permanent magnetic or an electromagnetic for producing the magnetic field. Whereas, the rotating part is coiled with insulated copper wire. When electric current moves through the copper wire in the rotating part, the electromagnetic forces between the static part and the rotating part comes into action and cause the rotating part to rotate and generate mechanical power.

This is the simplest definition of how a motor works, but for a detailed understanding of their working go to: https://www.explainthatstuff.com/electricmotors.html.

AC and DC Electric Motors

There are two broad categories of electric motors that rely on different type of currents to power themselves. These two categories are DC motors and AC motors.

• DC Motors – These motors need direct current for performing their functions. Direct current is the type of current which always flow one way – in a single direction. DC motors are commonly fitted with permanent magnets in their static part, but there also some motors that contain electromagnets instead of permanent magnets in their static part. DC motors are less common in heavy-duty
• AC Motors – These motors work on alternating current (AC) for performing their job. AC current is different from DC because it flows in two way – changes direction with a certain frequency in Hertz. AC motors don’t use permanent magnets in their static part, but use coils of wire for producing a magnetic field. AC motors are mostly used for heavy-duty tasks in factories and homes (e.g. for pumping water).

Uses of Electric Motors

Electricity is the most economical way of transferring energy to very large distances on wires. But we can’t use electricity directly to do our work, such as pumping water which requires mechanical energy. We need a way to produce mechanical energy from electricity to perform mechanical work. For this, we use electric motors that takes electricity at their input and gives mechanical power at the output.

Here are the main tasks on which we require electric motors:

• Electric Cars – These cars work on electricity which is mostly obtained from batteries in cars. They get mechanical power from electric motors instead of combustion engines.
• Industries – There are various processes in all kinds of industries in which we require mechanical power from electric motors, such as mixing, lifting, and pulling, etc.
• Electric Toys – Toys that perform some kind of movements require electric motors.
• Household – We rely on many electrical appliances to live comfortable that requires electric motors, such as air conditioner, electric fans, vacuum cleaner, water pump, grinder, and mixer, etc.

Facts

• Electric generators operate opposite to that electric motor; they produce electricity when their rotating part is turned by an engine.
• Theoretically, if you turn the rotating part of an electric motor, you will generate the same amount of electricity that the motor consumes to operate on that speed.
• Michael Faraday and Henry Joseph were the first to make the motion with electric current.

Transformers are one of the most important electrical machines that you may be familiar with. They can be observed on poles that distribute electricity to houses and building in many nations. But in developed nations and densely populated cities, it is very hard to find them on local poles because they are buried in the ground. Let’s learn about these amazing machines.

What Are Transformers?

Transformers are the electrical machines that are used to change the AC voltage, like in your power sockets, from one level to another. For example, if there is 220 volts (AC) in a power line and it needs to be converted into 110 volts (AC) then transformer will be used. Transformers can also be used to increase the voltage level (e.g. 110 volts to 220 volts).

How Transformers Work?

Transformers work on alternating current (AC) because they rely on the law of electromagnetic induction for functioning. In electromagnetic induction, when a magnetic field changes around an electrical conductor (wire), there will be a production of electrical current in that conductor. All the transformers rely on this principle for functioning.

A transformer is mainly made of three basic components; A core, primary winding, and secondary winding. The core is made of a material which enhances the magnetic field. Primary and secondary windings are the coils of wire that are wound on the core. These two winding are not connected together; only wound on the core separately.

When an alternating current is applied on primary winding, it will act as an electromagnet with changing magnetic field. The changing magnetic field will travel through the core and will pass through the secondary winding. Due to changing magnetic field, there will be the production of alternating current in the secondary winding.

For more information on magnetism, and to learn more about voltage, current, and resistance click here.

So, how much voltage will be produced in secondary winding? Find out by reading turn ratio of transformers.

Turn Ratio of Transformers

The production of voltage in secondary winding depends on a ratio, called turn ratio of a transformer. Turns ratio depends on the turns of wire wound on the primary and secondary winding.

For example: if there are 10 turns of wire on the primary winding and 40 turns on the secondary winding. Then, the turn ratio of the transformer will be 40 divided by 10 (40/10), which will be equal to 4. Now, multiply this turn ratio with voltage (AC) that is supplied to the primary winding. For example, if the applied voltage to the primary winding is 55 volts, then the voltage on secondary winding will be 55 × 4 = 220 volts.

The above-discussed transformer increases the voltage level from 55 volts to 220 volts, so it is called a step-up transformer. When a transformer decrease a voltage, suppose from 220 volts to 110 volts, it will be called a step-down transformer.

Uses

Transformers have played a vital role in the transmission of electricity over long distances. Prior to the transformer, transmission of electricity to hundreds of kilometers was very difficult and caused a lot of electricity loss. The loss was caused by heating-up of electrical conductors that carried the electricity. Because, when a current pass through a conductor it generates heat due to the resistance present in the conductors. By increasing the voltage of electricity, the amount of current can be reduced, which further reduces the waste of electricity and heating of conductors.

Today, power companies increasing the voltage (AC) on the conductors to transmit the electricity to large distances. When the electricity reaches to its consumers, for example to your house, it’s voltage is decreased (i.e. 220 volts or 110 volts) so that you can use it. Actually, there are a lot of transformers on the way, but the main purpose is same.

Here are a few more common uses of transformers:

• They are used in many household appliances to reduce the voltage to 12 or even low to be converted into DC so that the appliance can use it.
• These are used in sodium or neon street lamps to increase the voltage 11,000 volts to power the lamps.

Facts

• The idea behind the invention of electrical transformers was given in 1880.
• Many nations increase the voltage to 500,000 volts (500KV) or more to transmit electricity to thousands of kilometers away.
• You can’t use direct current in a transformer, because direct current doesn’t produce changing magnetic field.

Electrical relays are one of the important electrical devices that are used in many heavy-duty machines, such as air conditioners. These devices may be less known to common men, but any person having some technical knowledge probably know about it. Let’s understand these devices and their usage in more details.

What are Relays?

Relays are the electrical switches similar to the buttons on your electrical board for turning ON and OFF certain device. The basic purpose of a relay is similar to a switch, but they are slightly different. Relays can be turned ON and OFF by electric current, unlike a button which needs to be physically turned ON and OFF. For example, if you want to turn ON a relay which is normally OFF, you have to supply an electrical current to its sensing element. This property of relay to be turned ON and OFF electrically without the need for manual intervention is very useful, which you will know as you read the article further.

Types of Relays

All the relays can be categorized into two broad categories; electromechanical relay and solid state relay.

• Electromagnetic relays – These relays use an electromagnet and some moving parts for functioning.
• Solid State Relays – These relays don’t have any moving parts and are more efficient and reliable than the electromechanical relays.

How Relays Work?

A simple electromagnetic relay is made of an electromagnet, some moving parts, and contacts. The electromagnet is used as a sensing element which when receive electrical current, it closes or opens contacts of the relay – depending on relay type – to turn ON or turn OFF the load, e.g. compressor of an air conditioner and electricity supply to the home. The load can be any electrical device which you want to switch with a relay. The supply of electricity to the load goes from the contacts of relays which are opened and closed by an electromagnet when they receive electrical signal at their sensing element.

Solid state relay works very differently than electromechanical relay; they don’t have any moving parts. They rely on properties of the semiconductor for functioning. These relays are very reliable, durable, and fast compared to electromechanical relays, but they are very costly.

Uses of Relays

If we can switch a load with the help of a button on the electrical board, then why there is a need of relays? As I mentioned before, relays have the property that they can be switched electrical without the need of our physical intervention. For example, If you want your water pump to be turned off automatically when the water tank of your house fills completely. Then, you will use a relay and a kind of sensor for sending an electrical signal to relay when the tank fills completely. After receiving the signal, the relay opens its contacts to turn OFF the water pump.

Here are few more uses of relays:

• Switching ON heaving loads, such air conditioners or heavy motors, with the help of very small electrical current.
• For protection against short circuits, over-voltages, and under-voltages. When the protection relay will sense any of these conditions it will turn OFF the loads to avoid damages.
• Selecting between many loads. For example, you can use a relay to select and turn ON heater if the temperature drops very low, and select air conditioner if the temperature goes above the normal.

Facts

• Relays can be used to perform some arithmetic operation in computer applications.
• The first relay, that was an electrolytic relay, was designed by Samuel Thomas in 1809.
• Electromechanical relays were originally developed to transmit and receive telegraphs in 1840.