Capacitors n Dielectrics Flashcards
(25 cards)
What is a capacitor?
A capacitor is a device that stores electrical energy in an electric field.
What is the unit of capacitance?
The unit of capacitance is the Farad (F).
True or False: The capacitance of a capacitor depends on the voltage applied across it.
False.
What is the formula for the capacitance of a parallel plate capacitor?
C = ε₀ * (A/d), where C is the capacitance, ε₀ is the permittivity of free space, A is the area of the plates, and d is the separation between them.
Fill in the blank: The energy stored in a capacitor is given by the formula ______.
U = 1/2 C V².
What does the dielectric constant represent?
The dielectric constant represents the ability of a material to store electrical energy in an electric field compared to vacuum.
Which material is commonly used as a dielectric?
Materials like ceramic, plastic, and paper are commonly used as dielectrics.
True or False: Dielectrics increase the capacitance of a capacitor.
True.
What happens to the capacitance when a dielectric is introduced between the plates of a capacitor?
The capacitance increases.
What is the effect of increasing the distance between the plates of a capacitor on its capacitance?
The capacitance decreases.
What is the relationship between charge (Q), voltage (V), and capacitance (C)?
Q = C * V.
Fill in the blank: The dielectric strength of a material is defined as the maximum electric field ______.
that the material can withstand without breaking down.
What is the role of a dielectric in a capacitor?
The dielectric increases the capacitor’s ability to store charge by reducing the electric field between the plates.
What is the formula for the energy stored in a capacitor in terms of charge and voltage?
U = QV/2.
True or False: Capacitors can only store energy in the form of electric fields.
True.
What is a series connection of capacitors?
In a series connection, the total capacitance is given by 1/C_total = 1/C₁ + 1/C₂ + … + 1/C_n.
What is a parallel connection of capacitors?
In a parallel connection, the total capacitance is the sum of the individual capacitances: C_total = C₁ + C₂ + … + C_n.
Fill in the blank: The total charge in a series circuit of capacitors is ______.
the same on each capacitor.
What is the effect of temperature on the capacitance of a dielectric?
Temperature changes can affect the dielectric constant and thus the capacitance.
What is the purpose of a capacitor in an AC circuit?
Capacitors are used to block DC while allowing AC to pass, and to store energy temporarily.
True or False: The energy stored in a capacitor is directly proportional to the square of the voltage across it.
True.
What is the breakdown voltage of a capacitor?
The breakdown voltage is the maximum voltage that can be applied before the dielectric material begins to conduct electricity.
What happens to the energy stored in a capacitor when it discharges?
The energy is released as electrical energy to the circuit.
What is the significance of the dielectric loss tangent?
The dielectric loss tangent indicates how much energy is lost as heat in the dielectric material.
