Aluminium capacitors are very common electrical components that have been in use for over a century. They are electrolytic capacitors, which means that they have an electrolyte introduced into them, generally a paste in the case of these components.
An aluminium capacitor is a very simple device and the technology that makes it work dates back to the mid-1700s. A German scientist by the name of von Kleist is acknowledged as being the first to build a capacitor. The first common device that functioned as a capacitor, however, bears the name of a Dutch scientist, Leyden, who created the Leyden jar.
While the aluminium capacitor would come later, it shares much in common with the Leyden jar. The Leyden jar had metal on the inside and outside of the container. The glass provided the insulator against electricity flowing from one plate to the other, though the principle that creates capacitance was not fully understood at the time of invention.
The jar would be charged with a positive charge on the inside plate. The top was sealed with a stopper through which a metal chain descended. This was used to charge the device. Leyden discovered that he could discharge the capacitor he