Electronic devices should be powered by direct current supply DC (direct current) which is stable in order to work properly. The battery or batteries is a source of DC power supply is best. But for applications that require greater power supply, the source of the battery is not enough. Sources of power supply is a source of alternating AC (alternating current) from power plants. This requires a power supply device that can change the AC into DC current.
Rangkaian Power Supplay
Now it should not need another effort to make good pwer supplay you do not need to look for op-amps, transistors and other components, because these circuits are packaged into a single fixed voltage regulator IC. Are now widely recognized as a component of 78XX series fixed positive voltage regulator and the 79XX series is a voltage regulator to remain negative. Even these components are usually already equipped with current limiting (current limiter) and also limiting the temperature (thermal shutdown). This component is only three pins, and by adding some components alone can be a series of power supply regulation was good.
It's just to note that the IC regulator circuit that can work, the input voltage must be greater than the output voltage regulator. Usually the difference voltage Vin to the recommended VM is in the component datasheet. Usage heatshink (Aluminum cooling) is recommended if these components are used to supply large currents. In the datasheet, these components can pass the maximum current reached 1 A.