Here's how it works:

* Light-dependent reactions: Light energy is absorbed by chlorophyll in photosystem II, exciting electrons. These excited electrons move through an electron transport chain, releasing energy that is used to pump protons across the thylakoid membrane. This creates a proton gradient that is used by ATP synthase to generate ATP.

* NADPH production: The electrons eventually reach photosystem I, where they are re-energized by light. These energized electrons are then used to reduce NADP+ to NADPH.

In summary: Noncyclic electron flow uses light energy to create both ATP and NADPH, both of which are essential for the Calvin cycle (the light-independent reactions) to produce sugars.