History of electrochemistry
In 1789, Franz Aepinus developed a device with the properties of a "condenser" (now known as a capacitor.) The Aepinus condenser was the first capacitor developed after the Leyden jar, and was used to demonstrate conduction and induction. The device was constructed so that the space between two plates could be adjusted, and the glass dielectric separating the two plates could be removed or replaced with other materials.
Sprague Electric
Sprague used $25,000 of his savings to open Sprague Specialties Company at his home in Quincy, MA, in 1926. One of his first products was the mini condenser (an old name for capacitor). Mini condensers were commonly used in radio applications for noise filtering, signal coupling and tone controls. Early capacitors were two pieces of metal foil wrapped between wax paper or any other type of suitable insulation material. The type of insulating material determined the capacitor's capacitance and maximum voltage. Capacitors are also useful in high power applications like motors, and soon Sprague turned his attention those areas as well.