Capacitor Lab Report

INTRODUCTION

1. INTRODUCTION

1.1 Fundamentals of capacitor

Capacitor is very useful component in the field of engineering and it is used in various electrical and electronic circuitries. Capacitor stores energy in the form of electric field. Capacitor also known as condensers which stores energy when charge and release energy when discharge . There are different forms of capacitors which are used widely, but common thing about this all capacitors is that they are made of two conductors separated by single layer dielectric of uniform thickness [1]. Various dielectrics are used for capacitors such as vacuum, glass, mica, plastics, aluminium oxides etc. Dielectric in

It has been used for various applications like power factor improvement, timer circuits, and for various electronic circuits. Despite this, it has not been given required importance as compare to resistance and inductance. With development of supercapacitor in recent years, significance of capacitor has increased and it has provided new set of applications of capacitors in various electrical systems. Supercapacitor belongs to family of electrochemical capacitors. Supercapacitor is also known as electric double layer capacitor or ultracapcitors which store more energy than normal capacitor. Super capacitors are based on the same physical principle as normal capacitor. But normal capacitor has drawback of low capacitance. Supercapacitor has overcome such drawbacks and provides high capacitance in small volume [12]. They also have high energy density than conventional capacitors. Supercapacitors are composed of two electrodes immersed in an electrolyte solution. Main difference between supercapacitor and normal capacitor is supercapacitor provides high specific surface area with thinner electrodes as compare to normal capacitors [13]. Thus energy storage in double layer capacitor results from charge separation in thin layers formed between a solid conducting surface and liquid electrolytes containing ions. In supercapacitor charge does not accumulate between two conductors, but in between surface of conductor and electrolyte. The capacitance value of an electrochemical capacitor is determined by two storage principles, both of which contribute to total capacitance value of capacitor. Supercapacitor bridges gap between conventional capacitors and rechargeable batteries. They have the highest available capacitance values per unit volume and greatest energy density of all capacitors