I am trying to get the police light on #high speed brighter so I bought some led lamps. They are 12vdc, cob, 5 leds per unit. I wired 5 in parallel. The problem I faced was supply was 28VAC.
So I got a bridge rectifier, capacitor 25v (I know slightly under), and L7812 voltage regulator. I connected them, double checked polarity. When I turned it on for 5s, it didn't light... + lead to LEDs broke, and the cap was hot as hell.. it was only powered for 5 seconds or so. I checked components and triple checked polarity all fine. Later I saw cap voltage was polarized 1.5V.
What could cause cap to burn up, fact of overvoltage (since it's rectified AC, peak V is higher than 28v), fact it lost its load after VR, am i missing a needed component, or maybe my bridge rectifier is bad? A simple diagram is below.
Please note I am very depressed so I could be missing something simple or obvious , I couldn't even draw a proper schematic. Please advise.