Introduction to Electrical Engineering
Electrical engineering is one of the many disciplines within the engineering world. The engineer is to come up with a system that offers a solution to world problems. To achieve this engineering integrates scientific principles with mathematics to design and implement world solutions. Just like other disciplines, these solutions have been engineered thanks to the problems that faced mankind and by extension, this is still ongoing to date.
It’s unimaginable to think of a world without engineering concepts in place. While it’s not the only field that supports life to man, it’s enough to say it one of the vital bones that support human life. Engineering has been applied too generally all fields from agriculture, medical, transport, factories, communication, security and warfare to buildings and much more. Of the many branches of engineering is electrical Engineering which shall be our focus today. To start off it’s good to know that all these branches are interdependent and a common denominator is an electrical field. Barely would you come across a system without electrical subsystem, think of the house you are living, the car you are driving, the office you are working at, the recreational center you visit, the factory you work at, the religious center you visit just to name but a few.
What is electricity
Before delving deeper into this field lets first define what electricity is. This is a physical phenomenon associated with the presence and movement of electrons through a conducting material. It’s a form of energy that comes time to run almost all machines and gadgets that have been invented by man.
The history behind the discovery of Electricity
The discovery of static electricity comes by chance when some Greek’s rubbed amber with animal far, the observed that the amber attracted dry grass. Later there is the discovery of lightning as the movement of electric charge. A medical doctor discovered that whenever a frog touched two different kinds of metal its leg twitched, this was explained by Italian scientist voltage that there was the flow of electric charge through the frog hence making it twitch, which is more or less a shock. Volta discovered that whenever there is the electric potential between two objects and a conducting material such as metal or water connects them there is a flow of electric current. Discovery of electric charge was also made on vinegar where when two different metal rods were dipped inside and a wire joined them, electric charge flowed. He is the guy behind electric batteries.
By this time, we have discussed two types of electricity i.e. static or stationary and dynamic or moving electric charges. Further study of matter discovered these electrical charges consist of negatively charged electrons and positively charged protons, the electric charges in motion are electron due to their lightweight compared to protons. It’s prudent to mention here that there must be electric potential for charges to move.
Through thorough studies made by Charles Coulomb and advanced by Henry Oersted, a very important discovery was made, moving electric charges deflected a magnetic compass. Moving electric charges created magnetism that deflected the compass. Magnetism had earlier been discovered by blacksmiths who worked on metals to make tools. The theory of electromagnetism was developed by Andre Marie Ampere and James Clerk Maxwell. The relationship between these two phenomena is that electrons and protons, the minutes building units of atoms have both electric charge and magnetic field. It was Michael Faraday who discovered the opposite of Oersted, that changing the magnetic field can create a dynamic electric charge which is called electric current.
Now, this was a masterpiece breakthrough, if you can create a magnet by moving electric current and again you can create an electric current by moving electric charge it meant a lot in the energy sector. Magnetism is a form of energy given its ability to attract magnetic materials and this energy can be converted to electricity.
Through the experiment, a charcoal strip was connected to the two ends of a battery and amazingly the carbon in it glowed. Carbon filaments and later tungsten was used to make light bulbs which would light using batteries. Though electromagnetism ac electric generator and motor were discovered. Today there are millions of MW or GW (electric energy) generated by the generators and millions of machines run by the motors. The alternating current technology was championed by one Nikola Tesla who faced not a small resistance from Thomas Edson who maintained that AC cannot work at all. Today, however, the world runs on AC save for a few DC run machines/devices.
From this historical background, there have been massive inventions of generation, transmission, distribution, and consumption of electric energy. Electrical engineering is broadly divided into two, large signal or power or simply electrical and small-signal or electronics. Electronics deals with a signal whose voltage is usually 5V and its devices powered by 9V, 12V, 24V or 48V usually direct current voltage.
Read More about; Electricity Discovery
In terms of efficiency and transportability, this energy has no rival. Today any form of energy is converted to electricity that if it’s possible before being transmitted. Every single day inventions are made of gadgets that transform electricity into other desired forms. The good about electricity is its flexibility in so many forms.
- It is clean and environmentally friendly
- Easily convertible to other forms
- Easy to transport to different locations
- It’s very fast, travels at the speed of light
- It is silent, no noise.
To understand this discipline, I will subdivide into 2 main areas each of which shall form a college course one can pursue and become a professional in. these are;
This field is really the main one, some scholars have argued that electronics is part of electrical only that it deals with small-signal only. Today this term has been interpreted to means large signals or power. There are 4 main areas each depending on another to form a system. This is the electrical generation, transmission, distribution and loads.
As the name suggests this is the part that produces electricity. It’s the source of power that runs loads. There are two main types of generators that are direct current and alternation current generation. Electricity generator is basically a converter of energy into electrical form since energy cannot be created or destroyed. This source of energy can be renewable or non-renewable, renewable forms do not diminish despite being used while the other type diminishes every time it is used. The world is tending towards renewable sources to preserve the resources for posterity. The following are sources of electrical energy
Water at a high altitude than the generator- this water poses potential energy that is converted to kinetic form then to electrical form by the alternator.
Wind- moving air possess kinetic energy that is converted to electric energy by rotating wind turbines
Geothermal energy- underground high temperatures, heats water to steam which then rises by pressure this pressure is concentrated and directed to an alternator that then produces electricity.
Coal – this is a non-renewable source; heated coal is used to produce steam that runs the alternator to produce electricity.
Petroleum such as diesel- used to run diesel engines whose shaft is coupled to the alternator that produces electricity.
Solar energy- the sun poses energy that is convertible to electricity using a photovoltaic cell. The light and heat produce electricity that is usually used to charge a battery for use when the sun disappears at night.
Water waves and tides- the tides push the water towards the direction of the wind. These tides can be convertible to electricity using a suitable generator.
Nuclear energy- these are elements possessing high chemical energy such as uranium. This when burnt bursts forth to a lot of heat energy which heats water to steam that in turn produces electricity.
It’s worth keeping in mind that a battery is a storage device, it stores energy in the form of chemical energy and by connecting electrical load on its terminals it supplied direct current to it. It’s very critical and the only known device that stores electrical energy.
Electrical Power Transmission
Transmission or evacuation of power is the next step after production. While it will be convenient and cheap to generate power where the load is, this proves impractical as resources for generation are not available everywhere. Farther we will require a lot of generators to cater to the numerous device that needs this power, which goes against economies of scale and the cost of production becomes high.
Transmission or transportation is something inevitable to man, but thanks to electricity its transmission are quite easy. One generation point can serve millions of loads, the maintenance of this generation plant becomes manageable. It is worthy to note that today a single generation plant is capable of supplying enough power to a nation especially the developing once, these plants can produce hundreds of megawatts of electrical power steadily. To transmit power a conductor is required and, in this case, solid conductors are used.
Conductive metals are drawn into a cable or wire, this includes copper, aluminum and or alloys of aluminum, steel, carbon, etc. There are two ways of transmitting this power that is the overhead cable that is supported by poles or pylons and suspended by air (the air acts as the insulator), the other way in the insulated underground cable (buried in the earth). The widely used way is overhead as bear cables are cheap compared to insulated once. Based on the frequency of power generated, the voltage can be alternating or direct. Alternating to mean the magnitude of voltage varying with time from positive to negative a number of times in a second.
The power that a cable can carry depends on the resistivity of the material and the size of the conductor. For proper transmission to not overload the line as it heats up, maintain required insulation and clearance from other conductors and the earth. The world’s most used transmission is AC as it allows changing the transmitting voltage, usually, at the generation site, it is stepped up and at distribution center stepped down. Raising transmission voltage lower current which reduces power losses in the cable by heating up. In recent times, high voltage direct current transmission has been made possible. In historical research done by Nikola Tesla, it was proved possible to transmit power wirelessly, but this was not implemented as it posed danger to human life and communication signals distortion.
As the name suggests (this is the good thing about engineering, they don’t struggle for the jargon) this involves getting power to consumers. This consumer comprises all devices that must be powered by electricity for them to function. A station is set up to link transmission and distribution of power, at the heart of this station is a step-down transformer. The voltage needs to be lowered to be used by devices. On the output of the transformer are several distributions lines commonly known as feeder lines. The feeder lines are quite many and can be seen crossing over trucks of land, running by the roadside and for busy cities, the cables are underground.
There may be several levels of stepping down the voltage usually 2or more steps are used. Before user(s) are connected to power there is a distribution transformer that lowers the voltage to about 240V for British standard and 110V for the American standard. A distribution transformer is what powers you, it’s not just the presence of conductors and at this point, I may ask; do you know the transformer that power home or business?
If you don’t make an effort to find out. Always take caution not to get a touch or get near power transformer or live cable as you will be electrocuted and die. Within the power system, this is the most expensive and extensive network and can be very complex. Different generation station is usually interconnected to form a network commonly known as the grid. The power lines can evacuate electricity from different generators by manually or automatically operation switch gears.
These comprise all gadgets, devices, tools that function only when powered by electrical power. After the discovery of electricity, the first invention was the bulb. There were many scientists and technicians who did not small research on this but it is Thomas Edson who really came up with a long-lasting electric light bulb. This bulb came to be known as incandescent, at first using carbon-containing materials but later made of the tungsten filament. The invention of electric lighting was a game-changer and quite an enormous invention, to date this guy Edson is still esteemed for this.
Later on, the electric motor was invented and the fact that it could work by itself was just a big deal. The automation has said hello to the world. A machine that could work meant at a higher rate than man and feel no fatigue revolutionized the world. Industrialization was just beckoning. Electrical devices are nothing much than converters of electrical energy to a form that we need. Thanks to extensive and intensive research and innovation by dedicated scientists, engineers, and technician’s electrical energy have been converted to light, sound, movement, picture, heat, and many other phenomena.
Thanks to sensors or transducer’s invention, devices are self-operating making life comfortable and enjoyable to live. For motors converting raw materials to finished goods, to electric trains or vehicles, to bulb lighting at night, to the radio and television you watch, to the camera, to cookers to phones, to computers, to medical equipment electricity has become something we depend on so much. In fact, life comes to a standstill without power as services cannot be rendered. It’s interesting to note that the invention of devices is still ongoing and more are on the way. We shall handle this more in electronics.
This a branch of electrical engineering that deals with small voltage signals. It has been mistaken by some to be different from electrical engineering. The words come from a particle electron which the tiniest among the three in an atom. Atom is the building block of all materials on earth. In the market place electronics means devices for communication such as radio, TV, phone, computer, camera, projector et cetera. In engineering, the word means all components that are used to design and make devices that consume small voltage to operate. They include capacitor, resistor, inductor, diode, transistor, relay, switch, display screen, integrated circuit, oscillators just to name but a few. Much has improved in the electronics world with the entry of integrated circuited and printed circuit boards making it possible to make miniaturized devices.
One guy remains highly esteemed in the electronics world, and that is the inventor of the transistor. This function either as an electrical switch or an electrical amplifier depending on wiring. From transistor came integrated circuit, from which almost all electronic devices are made. The components that are used to make these devices are first losing their usage thanks to the programming of integrated circuit. The programming language has allowed setting transistors in IC to any desired functioned by deciding when to be on and off. The ICs have brought forth digital technology as opposed to analog one.
This branch is quite wide, it can farther be subdivided into communication, power electronics, and control engineering. Most control and monitoring work that was done by man is now accomplished using sensors, transmission, processors, display screen and result analyzers that make a self-sustaining system provided it is powered. One outstanding advantage of small signals is that it can be transmitted wirelessly. Speaker and microphone for voice communication were invented by alexander graham bell and through the work of Scientist Marconi, wireless radio communication was achieved. There is so many and vital inventions in this field that cannot be mentioned in this single write-up but the good thing is that these innovations are still ongoing.
Communication is one of the greatest needs of man after the vision. Edson had invented the light bulb but research continued on how we can communicate with a person beyond our hearing range. Two scholars as earlier mentioned (Edison and Graham Bell) are credited to making this possible. Wired telephone, wireless AM and FM radio, Television, mobile phones are all attributed to their efforts.
The invention of the internet or interconnected network allowed the sharing of information of people from any part of the earth. Using a computer and phone you can connect to the internet and surf any connect available on the data centers within a matter of seconds. The reliability of communication has allowed the business to thrive, relationships of families and friends to improve and even a chance for people to travel far off land so long as communication is there. The Internet has escalated learning or education as knowledge is shared globally and this is allowing more inventions to come up.
There are two main categories in this are i.e. telecommunication that deals with broadcasting media and Information communication technology dealing with computers and interconnectivity of devices for information sharing.
This is the world’s outstanding invention of a man. The first computer was the size of a room and required a team of technicians to operate, today that phone you have is a type of computer. The miniaturization was possible upon discovery of a transistor and later on the integrated circuit. Today a motherboard half the size of your palm has complex circuitry that you cannot comprehend. The printed circuit board has replaced wires making the end product look decent and appealing.
A computer consist of a central processing unit, memory or storage device, display and input devices. CPU is able to process millions of commands within a second far beyond the ability of a man. It comes as a package that has all human needs- typing, watching the video, listening audio, mathematical calculation, clock, internet access that connects you to the world. It can receive the software that allows achieving more than these basic functionalities thus a one-do-all device.
There are numerous devices that are simply computers from your mobile phone, laptop, medical equipment, media devices, plant control systems among others. Thanks to the programmability of these devices, identical hardware can be programmed to play different functions. The good this is some integrated circuits are reprogrammable. We will briefly look at programming.
In say 17th century, a machine using electricity was a huge one with complex sub-circuits. With the advancement of technology, the physical size of gadgets has been reducing while functionality has improved. This is was what betterment is. The miniaturization made a milestone when PCB and integrated circuit were invented. To date, the programmability of the integrated circuits has taken the technology world by storm. The possibility of downloading a huge program written in a language we can understand in a small chip which when a run does enormous tasks was a breakthrough.
The first programming language was called machine language. A transistor which is the basic component in machines(computers) functions as a switch with 0 and 1 values. 0 when off and 1 when on, this has come to be known binary numbers. Machine language was quite complex and a need for user-friendly language developed. Through many types of research, we have come from machine to middle and now high-level languages. A higher-level language has made programming so easy since you code using the language you can understand. A compiler was developed to convert the high level coded program to machine language. Some of the high-level languages include; C, C++, Java, and python. To specialize in this area, you need to study computer science, software engineering, information technology among others.
Today all computers run on the installed program. Software are divided into two broad categories namely; system software and application software. The system software is the operating system in any computer and phone, it manages all key functions of the device, it even application software’s to work. Application software, on the other hand, are made to perform a specific task, they can be installed or uninstalled from the device with affecting the machine. Examples include a calculator, a camera, a video or music player, a web browser, Microsoft Office applications among others.
Transducers or sensors
Before looking at the applications of this wide base of knowledge let’s have a look at one last component, these are sensors and transducers. This is a whole branch of knowledge that cannot be ignored. It’s the engine behind automation, the robots, the artificial intelligence just to mention a few. When we say you are alive, it’s because your systems are working right? Not really, you are alive when you respond to stimuli or external factor change. When someone approaches or even touches you, when a bell rings, when an egg is fried in next neighbor’s kitchen or when salt gets to your touch, what happens is that you sense then. We first sense, process the stimuli and respond either voluntary or involuntary most to our good.
In electrical engineering their myriad range of sensors triggered by stimuli. The basic functionalities of all sensors are either is analog or digital technology. In the analog different level of stimuli cause different levels of output from the sensor while in digital it’s a switch that turns on when a certain level of stimuli known as a threshold is reached.
A transducer is any device that converts a physical phenomenon into an electrical signal. Just like in a man we sense then respond to stimuli, sensor assets to display the presence and level of external stimuli for man to see. A sensor may be linked to actors that take action on the signal from the sensor. When darkness sets in you switch on lights, in the same way, a light-dependent resistor is a sensor that energizes relay at night, the relay closes contactor that switches on lights at night and switches off in the morning, hence achieving automatic operation.
Sensors have been used to make measuring instruments for natural phenomena such as heat, speed, distance, altitude and pressure. From the measurements taken, man has been able to make sound decisions that have made performance efficient. They have been widely used to measure water level in a tank, detect darkness, sense living things like animals, fingerprint capturing, temperature measurement, speed and distance sensor, items counter among others. The advantage of electrical sensors is in their efficient transmission of the signal to where it can be displayed or used to actuate a device in response to a received signal. In the same manner, command signals can be sent wirelessly by an operator to respond to sensor reading when in manual mode.
Robots, intelligent electronic devices, artificial intelligence, driverless vehicles and aircraft are just some powerful gadgets made of dozens of sensors and actuators. In attendance and security in a company, infrared sensors and thumbprint capture has been employed to manage staff. Drones have been used to capture images and sound of areas inaccessible my man to greater success. The extent to which transducers are going to affect technology cannot be overestimated.
Applications of electrical engineering knowledge
Having taken considerable effort to unwrap what electrical engineering is, it seems prudent for me to highlight some of the applications of this knowledge. Remember every effort of a man is to solve his problems, and electrical has done this is a great deal. We will briefly look at key sectors among the many that are applied.
Agriculture – it has seen great growth in farming practices. Water pumps have been used to take water from rivers, boreholes and lakes to the farm allowing farming in dry areas all the year-round boosting productivity. Smart irrigation is now a reality, where a moisture sensor determines when tap should open to spray water or close. Air conditioners are used to regulate temperature to horticultural crops in greenhouses allowing optimal temperature for high yields. In poultry farming, the incandescent bulb has provided light and warmth to chicks allowing health and faster growth. Processing of agricultural products using electrical plants and machines has allowed value addition, preservation and optimal production possible.
Military – Security systems have been improved thanks to electrical technology. The intelligent electronic device on automatic operation has been used to attack and destroy the enemy. From atomic bombs, unmanned vehicles, pilotless war jets weapons are commanded to fight by soldiers far from war site, this has made war a success without casualties on the attacker site. While this can be looked on a negative side when responsibly employed its quite effective. Drones have been used to spy the enemy before the attack. To a greater successful communication between forces in different locations but the same operation has been effective in making collective efforts bear fruits.
Education- This is the most impacted sector by this technology. Discovery of the electrical typewriter was a breakthrough in sharing knowledge in a write-up, later on, followed voice communication where a teacher could speak to a student and vice versa. Development of phones, computers, email, Microsoft Office, printers, fax machines, websites and applications has created a wide platform of sharing knowledge this has escalated the rate at which a learner acquires information.
The answers to questions are a click away. From sending and receiving lessons notes, books on word or pdf, video tutorial and live video calling, there is no better time as a time to learn. Information is circulating worldwide within a matter of seconds. Through the use of projectors, speakers, microphones, screens one can offer a lecture to a large class effectively, what an achievement.
Communication – this has brought a revolution. There is no longer a need to send a messenger to deliver a message which can reach the receiver by the click of a button. No need to trek miles away or even use other means of transport just to deliver a message. Communication has been eased so much so that the world has become a global village. Some of the electricity-dependent communication channels include hard-wired telephone, mobile phone, internet calling says through skype, email, social media platforms, radio, televisions, public address systems, websites, among many others.
To communicate to anyone in this word you just need their address and by dialing it you establish a communication link. Due to the improvement of communication equipment, the charges for connection are lowering day by day, this has improved human social interactions, cementing relationships and making life good. Teleconferencing has brought audiovisual communication to achieve milestones in business meetings.
Entertainment – the world has gone into a frenzy as much as entertainment is concerned. The audio-visual gimmicks have made events colorful, throbbing with life or as they say just lit. from loud music play to large screens for watching, the world is just fascinating. The light-emitting diodes have given a wide spectrum of colors in a myriad of patterns creating fun, joy and life to unwind any form of a stressful day to day activities. Most people flock these venues for a ‘life’ but just when electricity disappears, it’s all dark and silent, it’s like ‘death’ to them, this just tells you the role electricity plays.
In every home you will find a radio, television, a computer, phone, play station as a source of entertainment, all this uses electric power, in a power outage, everyone complains life is boring. It’s sad to note that we have neglected our active field entertainment events and replaced them with passive ones that have caused addiction to some. We should strike a balance as passive life brings lifestyle diseases sooner or later. Save for a drum and trumpet almost all other music instruments use electricity, now they say music is part of life so now you can see how it’s vital.
Lighting – the first device to use electricity was lighting bulb and today, the highest percentage of world electrical energy is used in lighting. If there was a dire need for man, then it was light. Lighting is required in dark rooms and offices in the day time and everywhere a man is at night for visual guidance. Light bulbs are installed in residential, commercial offices, factories, streets, town centers, religious centers, institutions and everywhere man is.
It’s this lighting at night that has allowed man to work before dawn and beyond dusk, achieving higher productivity. The 24-hour economy is a true goal when lighting is enough. Street lighting has adversely curbed insecurity cases and increased people’s confidence to walk around at night. With solar lighting that has no running cost, more and more areas have been lit even off-grid.
Automation – this is the self-operating system installed to offer service to man. Through actuator and sensor combination and computer programming, these systems are increasing day by day. Some of the automatic systems include- street lighting, driverless vehicle, pilotless aircraft, drones, robots, automatic industrial plants, smart homes, automatic irrigation systems, automatic animal feeding systems, automatic electric grid control among so many others. Through relays and programming, there is an ongoing invention to automate most systems. While this has created opposition due to job loss, in the long run, it will boost the economy, make life good and enjoyable at the same time. To some extent, automatic systems have performed better than man as numerous human errors are avoided.
A look at the future of Electrical Engineering
In conclusion, let’s cast an eye on the future of electrical engineering. So many inventions and discoveries have so far been made, have we reached saturation? By far, we are yet. Knowledge will never saturate, everyday university students, research institutions and lab technicians are working around the clock to produce the next device. A lot is happening in programming, software development, smart operating machines, automation, energy-saving machines or equipment, miniaturization, the durability of equipment, noiseless motors and generators, powerful sensors, good signal transmission among others.
I can guarantee you without fear of contradiction, there will be a technology boom, in this 21st century. For those considering delving deeper into electrical engineering, I would advise you to choose one branch according to your passion and relentlessly gather as much information as you can. The world statistics show a shortage of engineers and fear slow development pace with this shortage. Engineering is for the strong, the daring, the dedicated, the strong-willed, those who employ everything to achieve something. In engineering, the end is so important, how you maneuver around may not matter so much, because there are no shortcuts.