A farad is the unit of electrical capacitance in the International System of Units (SI). It measures a capacitor's ability to store an electric charge. One farad is defined as the capacitance of a capacitor that stores one coulomb of charge at a potential difference of one volt. Capacitance is crucial in various electronic devices, including capacitors, batteries, and power supplies. The farad is a large unit, so capacitors are often rated in microfarads (µF) or picofarads (pF) for practical applications. Understanding farads helps in designing and analyzing electrical circuits.