7809 Circuit Diagram
It is wise to use two .1uF capacitors on both input and output sides to filter any ripple or distortion in voltage but it is not necessary. In the image, you can see that 12V are being supplied on the input side of 7809 but the out put side of 7809 is outputting Regulated 9V. As long as the input voltage remains above 9V, output voltage of 7809 will remain smooth and regulated.
Please note that input voltage of 7809 can be up to 23V but under my experience, it is wise to avoid input over 15V. 7809 is claimed to output 9V and almost 1.5A Current but again, I have experienced that we should not put a load over 9V and 1A on it. Since we are using it in power supply, the transfer of power will result in heat output. We will need to use a heat sink with 7809 otherwise this heat can damage it. It is advised to use a 1A fuse on the output side of 7809 and a 1.5A fuse on the input side of 7809 to avoid damage in case of short circuit.
Posted or Updated On:Nov 04, 2009