All Flashcards
What is the definition of a capacitor?
A device that stores electrical charge and energy in an electric field.
Define capacitance (C).
The ability of a capacitor to store charge; measured in Farads (F), where 1 F = 1 C/V.
What are dielectrics?
Insulating materials placed between capacitor plates to increase capacitance.
What is the dielectric constant (κ)?
A value that quantifies how much a material increases capacitance when used as a dielectric.
What is an RC circuit?
A circuit consisting of a resistor and a capacitor connected in series, used for timing and filtering applications.
Define permittivity of free space (ε₀).
A physical constant that describes the ability of a vacuum to permit electric fields; approximately 8.85 x 10⁻¹² F/m.
What are the key differences between capacitors in series and parallel?
Series: 1/C_total = 1/C_1 + 1/C_2 + ... , Charge is the same, Voltage adds. | Parallel: C_total = C_1 + C_2 + ... , Voltage is the same, Charge adds.
Compare and contrast the behavior of a capacitor at t=0 and at steady state in a DC circuit.
At t=0: Capacitor acts like a short circuit, allowing maximum current flow. | At steady state: Capacitor acts like an open circuit, blocking current flow.
Compare charging and discharging in an RC circuit regarding current and voltage.
Charging: Current decreases exponentially, Voltage increases exponentially. | Discharging: Current decreases exponentially, Voltage decreases exponentially.
How do dielectrics work to increase capacitance?
- Polarization: Molecules align with the electric field, creating an opposing field. 2. Reduced Electric Field: Net electric field is reduced. 3. Increased Capacitance: More charge can be stored at the same voltage.
Describe the process of charging a capacitor in an RC circuit.
Current flows into the capacitor, voltage across it increases over time, and the current decreases exponentially as the capacitor charges.
Describe the process of discharging a capacitor in an RC circuit.
Current flows out of the capacitor, voltage across it decreases over time, and the current decreases exponentially as the capacitor discharges.