Solar powered calculators -- when do they use the solar panel, and when the battery?

Question

Are they connected in parallel? Do they use both?

How is it controlled - which power source to use at a given time?

Thanks a lot! :)

Answer 1

I would suspect there is a diode between the solar cell and the battery, or the battery would discharge through the solar cell when there is no light.

The battery is always in use, and the solar cell is putting current into the battery. In bright light there is a net positive current into the battery, charging it. In dim light, the battery discharges as it feeds current into the electronics.