The situation:
Let's say I am company XYZ who makes LED lighting bulbs for home use.
But I only have the technology to produce the non-dimmable version of LED lighting bulbs.
The TAM
would be the whole worldwide LED lighting market.
(Focus on total LED market)
My SAM
would be the worldwide non-dimmable LED bulbs market.
(Focus on your own technology/ what you can serve within the total LED market)