How it works
A solar panel (photovoltaic cell) converts light energy directly into electrical energy. When photons of light strike the semiconductor material, they knock electrons loose, creating an electric current when connected to a closed circuit.
A single silicon solar cell typically produces around 0.5V to 0.6V in direct sunlight. To achieve higher voltages (like 5V or 12V), many individual cells are wired together in series to form a solar panel.
The power a panel can deliver is highly dependent on light intensity and the load connected to it. It does not behave like a perfect battery; if you draw too much current, its voltage will rapidly collapse. To extract the maximum possible power, solar systems often use Maximum Power Point Tracking (MPPT) circuits.