A string inverter is a device used in solar energy systems to convert direct current (DC) generated by solar panels into alternating current (AC) that can be used in homes or fed into the electrical grid. It connects multiple solar panels in a series, or "string," allowing them to work together efficiently. String inverters are popular for residential installations due to their simplicity and cost-effectiveness. They are typically easier to install and maintain compared to other inverter types, such as microinverters or central inverters, making them a common choice for homeowners looking to harness solar power.