Ballast

Ballast are actually devices which steps down AC240.

They are potential energy waster becos it consumes energy and emits energy to its works.

In the past, downlights do not comes with electronic ballast built into the bulb itself.

But with the latest light bulbs which has electronic ballast built in it will not waste as much electricity energy even though these light bulbs cost 10%-20% more. It makes even more sense when the cost electricity is now at reocrd high.

check this out.

http://lighting.copperwire.org/82.php