Consider a solar light, which charges during the day and glows at night. Here, the capacitor stores the electrical charges. The simplest capacitor consists of two parallel conducting plates separated by a vacuum. When connected to a battery, electrons from the negative pole accumulate on the capacitor plate connected to it, developing a negative charge, while the other plate becomes positively charged. A potential difference that equals the product of the electric field and the distance between the plates is generated across the plates until it reaches the battery voltage. The electric field is proportional to the charge and the surface area of the parallel plates. Charged capacitors get discharged when connected to a load, and the electrons flow in the reverse direction untill the potential reaches zero. The quantity of charge stored in a capacitor to create a given potential difference is capacitance, measured in farad units. The capacitance for a parallel plate capacitor is directly proportional to the plate area and inversely proportional to the distance between the plates.