I have a Voltage Regulator. It is a L7805CP from ST. I want my circuit off of a 7.5V DC Adaptor. It is Tip Negative. Should I run the tip to input or ground on my Voltage Regulator, and vice versa with the outside. I wonder because I hear that voltage actually comes from negative side. Just wondering. Also if I hook my voltage regulator up backwards, will that ruin it? Thanks.