Arduino mega board 5v pin does not gives 5v when 7.5v is applied through external source I gave 7.5v to the arduino mega board through battery. 5v pin in the board gives me the same voltage as input. Earlier it was working fine now it is giving problem.Please let me know the solution as soon as possible.

Thanks and regards,
Thippeswamy
If you apply 7.5V to the power barrel jack and the 5V pin is 7.5V then your Arduino board is broken. Don't connect it to a computer. Don't use it anymore.