The inverter is commonly described as the brains of a PV solar panel installation and for good reason. The electricity from you solar panels comes in the form of "direct current" or "DC" for short. This is the same sort of electrical power that is provided by a normal battery and is characterised by the current flowing in the same direction. The electricity that comes to your house from the grid is known as "AC" or alternating current. In mains AC in the UK the flow of the current direction changes 50 times per second. This is caused by the way mains electricity has been generated traditionally. As a generator turns, large magnets and their magnetic fields cause electrons to be pushed this way and that as the coils come near the north and south poles.