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Power Supplies

Power Supplies

Power supplies are electronic assemblies that accept input power in whatever form is available and converts it to the form required for a given application - a common example is the charger for a cell phone. Power supplie may convert AC to DC, increase or decrease the voltage and current, and regulate (stabilize) the output so that it is unaffected by variations in the input power source. Power supplies also usually provide a means to adjust the output with a built-in control or by using an externally located control connected to it, or with a control voltage or digital input. It may also include some means for monitoring its output, such as an LED indicator or a meter. Power supplies may provide multiple outputs.

Power supplies are usually constructed as discrete assemblies containing nothing other than their own circuitry, though it may be mounted within the equipment they are powering. They may be enclosed in a metal case; however, a very small power supply (such as a cell phone charger) may be encapsulated within a plastic shell.

Power supplies consist of one or more transformers and smaller components such as semiconductors, resistors and capacitors. Because a power supply may dissipate a significant amount of heat, one should not be located in a confined space where that heat cannot be readily radiated to surrounding air.