Many circuits (including some MitchElectronics kits), require a 5V supply that is smoothed and reliable. The reason for this is that some components are not able to handle other voltages such as the buzzer found in many MitchElectronics kits which are rated for 5V operation only. If a different voltage is used then the component may either fail to work or even break! Creating a 5V source can be done with the use of the 7805 regulator but bread boarding a 5V source is cumbersome as breadboards are often large in size and inconvenient. This 5V source kit, however provides you with a 5V source that is compact, small, and convenient which takes a standard 9V PP3 battery and produces a stable and regulated 5V for all your 5V needs!