Electrical engineering is a discipline of technical sciences that deals with the technical applications of electricity and its physical constituents. It deals with the conversion of primary forms of energy into electrical energy, their transmission and distribution. It also deals with the conversion of electrical energy primarily into mechanical and thermal energy, and the transmission, switching and processing of messages and information.
The field can be divided into several aspects: first, direct and alternating current engineering. The latter is divided into two categories: low frequency technology, with alternating current technology (50 Hz line network) and the audio frequency range (up to about 20 kHz, telephony, electroacoustics), and high frequency technology, which includes the production and use of radio waves (communications engineering, radio technology, television) and microwaves.
The fields are often merged, for example radio transmissions are recorded as low frequency signals in the audio range, but transmitted with a high frequency carrier frequency (modulation). On the other hand, a distinction is made between high-current technology with voltages above about 250 V (generators, high voltage) and light-current technology (e.g. telecommunications, power tools). However, this designation is misleading, since the distinction is based on the voltage used, not the intensity of the current.
Electrical engineering in the broad sense also includes industrial applications of electric current, such as electrothermal technology (converting electrical energy into usable thermal energy), the construction and application of electric motors, e.g. for electric traction (electric traction, electric cars) or lighting technology.
Before the advent of semiconductor technology, electron tubes (vacuum diode, triode) played an important role in electrical engineering. Their tasks in switching and control technology are often taken over by semiconductor components such as transistors, which now form a separate field, electronics. Tubes are still important as tube generators for radio, microwave and X-ray production, and as cathode ray tubes, for example in televisions, computer monitors or oscillographs.
The oldest branch of electrical engineering is telegraphy. The first electric telegraph was built by S.T.v. Sömmering in 1809. With the discovery of the dynamo-electric principle by W.v. Siemens in 1866 and the subsequent development of the electric generator and motor. Electrical engineering had a turbulent development, closely linked to the industrial revolution at the end of the 19th century. The next steps were the invention of the telephone (1861 / 1876), three-phase current (1885) and electron tubes after World War I.
An electrical engineer is responsible for a wide range of tasks. This includes, for example, checking electrical devices, systems or machines for faults and then putting them into operation. He or she is also responsible for wiring and programming assemblies and various maintenance tasks.