Batteries come in many different sizes. Some of the tiniest power small devices like hearing aids. Slightly larger ones go into watches and calculators. Still larger ones run flashlights, laptops and vehicles. Some, such. Capacitors can serve a variety of functions. In a circuit, they can block the flow of direct current(a o. A battery can store thousands of times more energy than a capacitor having the same volume. Batteries also can supply that energy in a steady, dependable stream. But som. In recent years, engineers have come up with a component called a supercapacitor. It's not merely some capacitor that is really, really good. Rather, it's sort of some hybridof ca.