In film cameras, ISO referrs to the sensitivity to light of the emulsion.
Manufacturers formulate different film emulsions with different
sensitivites tarding increased grain with increased ISO speed.

In a digital camera, presumably the sensor does not adjust itself to have
greater sensitivity. Or does it?

So what is happening in a digital camera when I choose a greater ISO
setting? Is more amplification being used?

I tried to understand this page but it got far too technical....

https://photography.tutsplus.com/art...n--photo-11963