Check out our Full Indepth Saw Stop Demo, including changing a out a new cartridge and blade. 

Doesn't matter how many times I see this demo. I'm amazed every single time. That's an insane invention.

Lantern Labs has a patent on a circular saw kickback stop device. It's pretty slick. They showed it while the patent was pending at one of the inventors channels, Smarter Every Day. Destin is some sort of rocket engineer, IIRC.

This is great for safety reasons but they are flawed because they operate of of continuity as a result of this green or damp wood can trigger the saw stop its a $200+ repair