My arduino gets hot when us a 12 volt adapter

Pity they didn't build one onto the arduino, then this conversation wouldn't be taking place. Everybody would complain if the price went up by $10/£7 though. At the current UK ripoff prices for electric the pay back for saving a single watt is around £1 a year. In cold climates its not a total loss indoors, it contributes to the space heating. You pays your money and...........