This question already has an answer here:
Why is it that DSLRs makes more bokeh from far objects compared to near ones (Large apertures)? How camera sensor (or lens) function to take this shots?
My question is different as in the link above it says aperture is same on both APS-C and the other. My question is how
bokeh is generated on DSLRs?
How should I explain this? The second question mentioned in above links tells something like:
Wide aperture lenses give you a shallower depth of field
And similar explanation. But I need the theory behind it that camera uses to blur subject. For instance why
wide aperture gives shallower depth of field. What makes it shallow and how? In which part of the camera this happens?