Capacitors Flashcards
What do capacitors do?
Capacitors store and release electrical energy, filter signals, and stabilise voltage in circuits.
How do capacitors work?
They store energy in an electric field between two conductive plates separated by a dielectric material.
What are the main types of capacitors?
Ceramic, electrolytic, tantalum, film, and supercapacitors.
What is a ceramic capacitor?
A capacitor made with a ceramic dielectric, used for high-frequency and low-value applications.
What is an electrolytic capacitor?
A polarized capacitor with high capacitance, used for filtering and power supply applications.
What is a tantalum capacitor?
A polarized capacitor with high stability and reliability, used in compact circuits.
What is a film capacitor?
A capacitor with a plastic film dielectric, known for precision and stability.
What is a supercapacitor?
A capacitor with extremely high capacitance, used for energy storage and backup power.
What is the capacitance of a capacitor measured in?
Farads (F), typically in microfarads (μF), nanofarads (nF), or picofarads (pF).
What is the voltage rating of a capacitor?
The maximum voltage it can handle without breaking down.
What is the role of the dielectric in a capacitor?
To increase capacitance by preventing current flow while allowing electric field storage.
What is a polarized capacitor?
A capacitor with a positive and negative terminal, such as electrolytic and tantalum capacitors.
What is a non-polarised capacitor?
A capacitor that can be connected in any orientation, such as ceramic or film capacitors.
How are capacitors used in filtering?
They smooth out voltage fluctuations by bypassing AC signals while blocking DC.
What is a decoupling capacitor?
A capacitor placed across power supply lines to filter noise and stabilize voltage.
What is a coupling capacitor?
A capacitor used to pass AC signals while blocking DC, often in audio circuits.
What is the equivalent series resistance (ESR) of a capacitor?
The internal resistance that causes power loss and affects performance at high frequencies.
What is a variable capacitor?
A capacitor whose capacitance can be adjusted, used in tuning circuits.
How do you calculate the total capacitance of capacitors in series?
1 = 1 + 1
CTOT C1 C2
How do you calculate the total capacitance of capacitors in parallel?
CTOT = C1 + C2
What are common applications of capacitors?
Energy storage, signal filtering, timing circuits, and voltage stabilisation.
What can go wrong with capacitors?
Leakage, overheating, short circuits, or dielectric breakdown.
How do you test a capacitor?
Use a multimeter or capacitance meter to measure its value and check for shorts or opens.
What is a high-voltage capacitor?
A capacitor designed to handle high voltages, often used in power transmission systems.
What is a low-ESR capacitor?
A capacitor with low equivalent series resistance, ideal for high-frequency and high-current applications.
How do temperature changes affect capacitors?
They can alter capacitance, especially in ceramic and electrolytic capacitors.
What is a bypass capacitor?
A capacitor used to bypass AC noise to ground, improving power supply stability.
What is the self-healing property of film capacitors?
The ability to repair minor dielectric breakdowns, extending their lifespan.
What is a safety capacitor?
A capacitor designed to fail safely, used in AC line filtering to protect against surges.
How do you ensure proper capacitor usage?
Select the correct capacitance, voltage rating, and type for the specific application.
