Capacitor Knowledge Exchange

How does the mode of operation of a capacitor affect life and reliability?

Particular emphasis is given to the influence of the mode of operation of the capacitor upon life and reliability, including energy discharge, low- and high-frequency filtering in AC and DC systems, AC resonant inverters, and switch-mode power supply use, along with transient pulse filtering applications.

How do you connect a capacitor to the outside world?

The connection to the outside world is often made by soldering tabs to the electrode. A second method of making a connection to this type of capacitor is to spray the extended foil with a molten metal. This operation is commonly referred to as end spray. Once this is completed, a tab is soldered to the end spray.

How does a capacitor work?

A capacitor generally consists of metallic conducting plates or foils separated by thin layers of an insulating medium, with the plates on the opposite sides charged by a voltage source; the resultant electrical energy of this charged system is stored in the polarized insulating medium.

How is a capacitor measured?

A capacitor is measured by the size of its capacitance. A capacitance is the electric capacity of a capacitor, i.e. the amount of electrically charged carriers it can store. ɛ r . The relative dielectric constant can have values between ɛ r = 1 (air) and ɛ r ~ 10,000 (special ceramic materials).

What is the energy stored on a capacitor?

where W is the stored energy on the capacitor (Joules), Q is electric charge stored on the capacitor, C is capacitance, and V, voltage across the capacitor. The equation illustrates that energy stored on a capacitor is largely dependent on the capacitance and voltage of the capacitor.

How long does a capacitor last?

In the 40-65 °C range, experimental data show that the life of the capacitor is decreased by a factor of 2 for every 8 °C of temperature increase. Above 65 °C, new failure modes have emerged, and the capacitor cycle life begins to degrade quickly.