MEMS devices operate by converting energy from one form to another. For instance, a MEMS sensor can convert mechanical energy (such as pressure or acceleration) into electrical signals that can be processed and analyzed. This is achieved through the use of microfabrication techniques, which allow the creation of intricate structures on a microscale using materials like silicon. The integration of mechanical and electrical components on a single chip enables MEMS devices to perform complex functions with high precision and reliability.