Lexicon Power Supply
A power supply unit is the component in a mains-operated electronic device that is responsible for the power supply. It is necessary because electronic devices can usually not work directly with the mains voltage. Most electronic devices in the hi-fi sector require DC voltages in the range of 3V to over 100V for operation, depending on the case. Not infrequently, several different DC voltages are required at the same time. It is the task of the power supply to generate these DC voltages from the AC voltage of 230V available in the mains.
The simplest type of power supply, which is still widely used in hi-fi equipment, is based on a mains transformer. In addition, rectification, filtering and possibly voltage regulation are required. The constructive simplicity of this variant is contrasted by the resulting size of the transformer, especially in power amplifiers with their high power requirements. This component consists of an iron core and copper coils, and its size and weight increase with the power requirement. A large part of the weight of a power amplifier is thus due to the power transformer.
The increasingly popular alternative to this is the switched-mode power supply. This principle is dominant in computers today. Here the mains voltage is directly rectified and then chopped up again at a much higher frequency. Only then does a transformer come into play, which, because of the higher frequency, can be much smaller, lighter and cheaper than with the conventional power supply. Despite the greater complexity, money can often be saved due to the material savings. However, the chopper produces interference pulses which have to be reduced again by suitable filtering.
In hi-fi equipment the power supply is usually integrated into the unit. In some cases, however, external power supplies can be found which are housed in a separate enclosure and connected to the actual device by cable. In the case of small devices, this is widespread due to the use of plug-in power supplies. Here, too, you can find both functional principles. An external power supply can make it easier to protect sensitive electronic circuitry from the effects of stray magnetic fields and other interference coming from the power supply, primarily due to the greater distance between the power supply and the device.
See also:
- Wikipedia article power supply