Incandescent light bulb was one of the first applied electric light sources in history. In order to work, it requires only a power supply voltage. Its main weakness is poor luminous efficiency, because only about 10 % of the electricity is transferred into light. The remaining energy is lost as heat. [1] Finding new electric light sources, which have better light efficiency than incandescent light bulbs led to the development of gas discharge lamps and light-emitting diodes later. Gas discharge lamps and light-emitting diodes require suitable ballasts or LED drivers in order to be in line with operation regulations.
The aim of this thesis is to present different types of ballasts for discharge lamps and power supplies for LEDs. In the past, ballasts operated on the principle of magnetic circuits, today, for the operation of a variety of lamp types electronic ballasts are increasingly used. Along with the development of LEDs, also suitable drivers for them were invented. The thesis gives an overview on different types of ballasts and power supplies for LEDs. It also describes the principles of their operation and the various principles of regulation of the luminous flux.
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