Capacitor uses

The pioneering years in the history of capacitors was a time when capacitors were used primarily for gaining an early understanding of electricity, predating the discovery even of the electron. It was also a time for doing parlor demonstrations, such as having a line of people holding hands and discharging a capacitor through them. The modern era of capacitors begins in the late s with the dawning of the age of the practical application of electricity, requiring reliable capacitors with specific properties.

The transmitters built up a high voltage for discharging across a spark gap and so used porcelain capacitors to withstand that voltage. High frequency was also required.

Function of capacitor in a circuit

These were basically Leyden jars and to get the required capacitances took a lot of space. In , William Dubilier invented smaller mica capacitors which were then used on the receiving side for the resonant circuits in wireless hardware. Being just mica sheets pressed against metal foils, there were air gaps between the mica and foils. Those gap allowed for oxidation and corrosion, and meant that the distance between plates was subject to change, altering the capacitance.

In the s silver mica capacitors were developed, ones where the mica is coated on both sides with the metal, eliminating the air gaps. With a thin metal coating instead of thicker foils, the capacitors could also be made smaller. These were very reliable. The modern era of capacitors has been marked by one breakthrough after another for a fascinating story.

MLCCs around a microprocessor.

Capacitor formula

They were produced in small quantities at first and larger quantities in the s. They consisted of a disc metalized on both sides. To get higher capacitance another ceramic, barium titanate was used, as it had 10 times the permittivity of mica or titanium dioxide.