Capacitor Questions and Answers for Viva

Answer-1: Passive

Answer-2: Electrical energy

Answer-3: A.C. current

Answer-4: Ceq. = C1 + C2

Answer-5: C = Q/V

Answer-6: Capacitor store energy in the form of electrical energy where as inductor store energy in form of magnetic energy.

Answer-7: Impregnated paper was extensively used for older capacitors, using wax, oil, or epoxy as an impregnant. Oil-Kraft paper capacitors are still used in certain high voltage applications. Has mostly been replaced by plastic film capacitors.

Answer-8: Very large capacitance to volume ratio, inexpensive, polarized. Primary applications are as smoothing and reservoir capacitors in power supplies.

Answer-9: Air-gap: air-gap capacitors have a low dielectric loss. Large-valued, tunable capacitors that can be used for resonating HF antennas can be made this way. Ceramic: the main differences between ceramic dielectric types are the temperature coefficient of capacitance, and the dielectric loss. C0G and NP0 (negative-positive-zero, i.e. ?0) dielectrics have the lowest losses, and are used in filters, as timing elements, and for balancing crystal oscillators. Ceramic capacitors tend to have low inductance because of their small size.

Answer-10: Capacitor have thin conducting plates (usually made of metal), separated by a layer of dielectric, then stacked or rolled to form a compact device. Many types of capacitors are available commercially, with capacitance ranging from the picofarad, microfarad range to more than a farad, and voltage ratings up to hundreds of kilovolts. In general, the higher the capacitance and voltage rating, the larger the physical size of the capacitor and the higher the cost. Tolerances in capacitance value for discrete capacitors are usually specified as a percentage of the nominal value. Tolerances ranging from 50% (electrolytic types) to less than 1% are commonly available. Another figure of merit for capacitors is stability with respect to time and temperature, sometimes called drift. Variable capacitors are generally less stable than fixed types.

Answer-11: Capacitor is a device for storing charges. It consists if two metal plates placed parallel with a dielectric or an insulating medium in between them.

Answer-12: The capacity of a capacitor is numerically equal to the quantity of charge which must be given to the condenser in order to maintain the unit potential difference between the plates.

Answer-13: It depends on
a) area of the plate
b) distance between the plates is called dielectric constant of the material used.

Answer-14: It is defined as the time required for the capacitor to charge to 63% of its maximum value. It is equal to the product of R & C.

Answer-15: The discharge takes place through the resistance.

Answer-16: Equal to the applied voltage.