7805 regulator heats up/fails
3 Amps @ 5 v. Input 9 - 18Vdc
http://www.newark.com/jsp/displayProduct.jsp?sku=52R2842
The above is smoothed out regulated reliable power. Not just a VR.
I spent a couple years making 5 V, 12 V, 18 Volt and adjustable VRs in all kinds of variations for communications projects and you simply cannot beat the reliability and smooth power output of a production unit designed to suit the job. In the end we gave up on fabrication as it was neck in neck with purchase price of production units and started buying production units. For several years we were replacing the hand fabricated voltage regulators in the field about once a year (by the hand fulls).