Unformatted text preview: gnetic field (charge in motion / current). Capacitance and inductance are employed in designing transducers to measure other physical quantities. Filters made up of inductance and capacitors are used to remove unwanted noise from measurement signals. However, these elements do not generate energy and hence are still known as passive elements. These also are linear elements in the sense that current and voltage for these elements hold a linear relationship, albeit of integral‐differential nature. Capacitance Capacitors are constructed by separating two sheets of conductors by a thin layer of insulating material. The insulating material is called dielectric and it can be air, paper, Mylar, polyester etc. When a DC voltage source is connected across a capacitor, then electrons get repelled from the negative terminal of the source towards the capacitor, but stop at the insulating material ( as they cannot pass through). Similarly, electrons from the other side of the capacitor get attracted to the positive terminal of the voltage source. Thus, the two plates of the capacitor get charged oppositely. An electric field is developed inside the insulating material, from positively charged plate towards the negatively charged plate. A voltage develops across the capacitor which equals the vo...
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This document was uploaded on 01/20/2014.
- Winter '14