Electrical Engineering BMT & UFC
In this tutorial you will find all lecture content for "Fundamentals of Electrical Engineering" in the BMT degree programme at HSHL in Hamm.
Motivation
Why electrical engineering? The subject is difficult, nerdy and does not have a good reputation. So why should you learn electrical engineering with enthusiasm? Because electrical engineering can do a great deal. And if you master it, you can achieve a great deal.
About 100 years ago, the world was predominantly mechanical. Devices were made of metal or wood, and drives were mostly powered by burning coal. However, the possibilities of mechanics for moving things are very limited. Take as an example a toy car that is to be moved. It should move autonomously, without someone constantly pushing it.
For this we need an energy store. In mechanics we use springs, for example. So in the toy car a coil spring is tensioned when the car is wound up. It is then released and drives – hopefully straight ahead – until it stops. The fun is limited, because it is not possible to intervene in the system while it is driving. The "charging" of the energy store is done by the same movement as driving, only backwards. That is not much fun to drive.
If we build the same system electrically, the energy store is a battery. It is charged via a power supply at a socket. Enough energy can be stored in the battery for the car to drive around for hours. The stored energy not only initiates a movement, but also powers steering, a remote control and a drive with adjustable speed for moving forwards and backwards. That is fun!
Even this example shows how flexibly electrical energy can be used. The spring can only deflect in the direction opposite to the one in which it was tensioned. The intensity of the relaxation – i.e. the release of energy – cannot be adjusted. Mechanically stored energy is very inflexible. It is also hard to transport. You need an enormously large and stiff spring to get as much energy as is already stored in a tiny watch battery a few millimetres in diameter.
Mechanical systems, such as the car with a combustion engine, carry stored energy in the form of petrol. But burning the fuel is also inflexible. It only turns a shaft. A drive for the wheels then has to be realised laboriously from the rotary motion. For steering, braking, lighting and listening to music you need another energy source. In the car, the energy of the fuel is converted into electrical energy in the alternator, so that this flexible form of energy is also available in the car. The trend is clearly towards the purely electric car, so that this nonsense from a bygone era finally stops. Modern combustion engines are extremely complex. Electric motors are very simple in design, and they also cost much less than combustion engines.
The present and above all the future belong to electrical energy. Especially because it is so difficult to produce conventional fuels from renewable sources. Electrical energy can be obtained quite easily from wind energy, solar energy or natural chemical processes. It can then easily be converted into any other form of energy.
There is a very convenient supply network for electrical energy. You will find sockets everywhere at which you can use electrical energy. More and more devices are becoming portable and independent of sockets, because electrical energy can be stored ever more efficiently and with ever greater energy density.
In this tutorial you will learn how to use electrical energy in your projects. We start with the physical fundamentals of electric charge. Then you will get to know voltage and current. You will learn how to dimension these quantities correctly for a load. And you will get to know electrical storage elements and their behaviour in circuits. At the end, I will explain how AC networks are calculated and designed, so that you can also operate your systems from a socket.
I hope you enjoy reading and wish you every success in understanding!
Holger Glasmachers