ac engineering or electronic engineering
Hello,Faraz
AC engineers, also known as AC technicians, install and maintain the mechanical and electrical components of air conditioning systems. They may diagnose and repair air-conditioning problems throughout homes or buildings.
Electronic engineering (also called electronics and communications engineering) is an electrical engineering
discipline which utilizes nonlinear and active electrical components
(such as semiconductor devices, especially transistors, diodes and
integrated circuits) to design electronic circuits, devices, VLSI devices ...
Hope this helps.