An electrical assembly includes an electrical connector mounted upon a PCB and receiving a CPU therein, and a liquid Nitrogen heat dissipation device is mounted upon the PCB and intimately seated upon the CPU to remove the heat therefrom. The liquid Nitrogen heat dissipation device includes a case forming a chamber to receive the liquid Nitrogen therein. A plurality of fixing arms extend outwardly and radially to fix the liquid Nitrogent heat dissipation device in position. A fixing seat is attached upon the PCB to precisely located the CPU in position with regard to the electrical connector.