Instructables

How To Make A Simple Piezo Doorbell - Duration Adjustable - Project#1 Electronics Learning Board

Step 1: The 7805 5v regulator

Picture of The 7805 5v regulator
Our digital circuitry may very well be sensitive to over-voltage.  While the 555 timer circuit can handle a power supply of 5v, the 5v piezo buzzer cannot.  Most projects like this would require a 9v battery.  How to we easily regulate down to 5v?  Easily!  With the help of our trusty and inexpensive friend, the 7805 5v regulator IC.  This IC has an input port (1), a ground port (2), and a regulated output port (3).  The power supply circuit, including the 7805 is talked about in depth in the below video!  In order to regulate down to 5v, you need at least 7VDC at the input pin.  If after watching this video, you have any questions, please do not hesitate to post them below!  I'll do my best to answer!