ENERGY
UNIVERSE Knowledge educational article.
A photovoltaic solar panel converts part of the energy carried by sunlight into electrical energy. The process depends on semiconductor physics, electric fields, circuit design and power electronics.
Sunlight contains photons with different energies. When photons with sufficient energy interact with a semiconductor such as silicon, they can transfer energy to electrons and create mobile charge carriers.
A photovoltaic cell contains a junction between semiconductor regions with different electrical properties. The internal electric field helps separate charge carriers, producing a voltage that can drive current through an external circuit.
Individual cells produce limited voltage and current. Cells are electrically connected into modules and panels so that the output meets practical voltage and power requirements.
Solar output depends on irradiance, cell temperature, shading, orientation, spectral conditions and electrical loading. Power electronics such as maximum power point tracking help extract useful power under changing conditions.
If a small system operates at 20 V and 5 A, its electrical output is P = VI = 100 W before considering conversion and wiring losses. Engineers then size batteries, controllers, conductors and loads around the expected operating conditions.