5-18V Stabilized Power Supply

This power supply will give you fixed regulated output at 5V, 6V, 9V and 12V, while the 18V output is unregulated. You could add some regulated IC like LM7815 or 7818 if you need higher output voltage.
electronic circuit diagram

This circuit provide an audio indicator that will act like an alarm if any circuit short contact.

About Power Supply
A power supply is a device that supplies electrical energy to one or more electric loads. The term of "power supply" is most commonly applied to devices that convert one form of electrical energy to another, though it may also refer to devices that convert another form of energy (e.g., mechanical, chemical, solar) to electrical energy.
A power supply may be implemented as a discrete, stand-alone device or as an integral device that is hardwired to its load. In the latter case, for example, low voltage DC power supplies are commonly integrated with their loads in devices such as computers and household electronics. More explanation about power supply can be found at wikipedia.org

This is the tutorial about "How to build an AC to DC power supply ". The video tutorial covers the basics of diodes, bridge rectifiers, and how to build simple unregulated AC to DC power supplies than can handle a few mA up to several Amps.

Watch the video: