Technology
How does a solar panel work?
A solar panel works using the photovoltaic effect: when sunlight hits its silicon cells, it knocks electrons loose, and a built-in electric field pushes those electrons into a current. Wire many cells together and that flow becomes usable electricity.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how a solar panel works.
Step by step
- 1Each cell is silicon 'doped' into two layers that meet at a junction with a built-in electric field.
- 2Photons of sunlight knock electrons free from the silicon atoms.
- 3The junction's field forces the freed electrons to flow one way, creating direct current (DC).
- 4An inverter converts that DC into the alternating current (AC) that homes and the grid use.
- 5More light and larger panel area mean more current; efficiency is typically 18–22%.
Frequently asked questions
- Do solar panels work on cloudy days?
- Yes, but less. They still capture diffuse light, producing perhaps 10–25% of their sunny-day output depending on cloud thickness.
- What is the photovoltaic effect?
- It's the process where light frees electrons in a material and a built-in electric field drives them into a current — the core of how solar cells make electricity.
- Where does the electricity come from at night?
- Panels make none at night, so a home draws from the grid or from a battery charged during the day.