StudySmarter - The all-in-one study app.

4.8 • +11k Ratings

More than 3 Million Downloads

Free

StudySmarter AI is coming soon!

- :00Days
- :00Hours
- :00Mins
- 00Seconds

A new era for learning is coming soonSign up for free

Suggested languages for you:

Americas

Europe

The capacitance of a capacitor is measured in Farad and is the amount of energy it can store. Capacitors are used as crucial components of electrical circuits in many modern devices, including pacemakers, mobile phones, and computers.Capacitors are commonly used to store electrical energy and release it when needed. They typically feature in combination with other circuit components to produce a filter that allows…

Content verified by subject matter experts

Free StudySmarter App with over 20 million students

Explore our app and discover over 50 million learning materials for free.

Capacitor Discharge

- Astrophysics
- Absolute Magnitude
- Astronomical Objects
- Astronomical Telescopes
- Black Body Radiation
- Classification by Luminosity
- Classification of Stars
- Cosmology
- Doppler Effect
- Exoplanet Detection
- Hertzsprung-Russell Diagrams
- Hubble's Law
- Large Diameter Telescopes
- Quasars
- Radio Telescopes
- Reflecting Telescopes
- Stellar Spectral Classes
- Telescopes
- Atoms and Radioactivity
- Fission and Fusion
- Medical Tracers
- Nuclear Reactors
- Radiotherapy
- Random Nature of Radioactive Decay
- Thickness Monitoring
- Circular Motion and Gravitation
- Applications of Circular Motion
- Centripetal and Centrifugal Force
- Circular Motion and Free-Body Diagrams
- Fundamental Forces
- Gravitational and Electric Forces
- Gravity on Different Planets
- Inertial and Gravitational Mass
- Vector Fields
- Conservation of Energy and Momentum
- Dynamics
- Application of Newton's Second Law
- Buoyancy
- Drag Force
- Dynamic Systems
- Free Body Diagrams
- Normal Force
- Springs Physics
- Superposition of Forces
- Tension
- Electric Charge Field and Potential
- Charge Distribution
- Charged Particle in Uniform Electric Field
- Conservation of Charge
- Electric Field Between Two Parallel Plates
- Electric Field Lines
- Electric Field of Multiple Point Charges
- Electric Force
- Electric Potential Due to Dipole
- Electric Potential due to a Point Charge
- Electrical Systems
- Equipotential Lines
- Electricity
- Ammeter
- Attraction and Repulsion
- Basics of Electricity
- Batteries
- Capacitors in Series and Parallel
- Circuit Schematic
- Circuit Symbols
- Circuits
- Current Density
- Current-Voltage Characteristics
- DC Circuit
- Electric Current
- Electric Generators
- Electric Motor
- Electrical Power
- Electricity Generation
- Emf and Internal Resistance
- Kirchhoff's Junction Rule
- Kirchhoff's Loop Rule
- National Grid Physics
- Ohm's Law
- Potential Difference
- Power Rating
- RC Circuit
- Resistance
- Resistance and Resistivity
- Resistivity
- Resistors in Series and Parallel
- Series and Parallel Circuits
- Simple Circuit
- Static Electricity
- Superconductivity
- Time Constant of RC Circuit
- Transformer
- Voltage Divider
- Voltmeter
- Electricity and Magnetism
- Benjamin Franklin's Kite Experiment
- Changing Magnetic Field
- Circuit Analysis
- Diamagnetic Levitation
- Electric Dipole
- Electric Field Energy
- Magnets
- Oersted's Experiment
- Voltage
- Electromagnetism
- Electrostatics
- Energy Physics
- Big Energy Issues
- Conservative and Non Conservative Forces
- Efficiency in Physics
- Elastic Potential Energy
- Electrical Energy
- Energy and the Environment
- Forms of Energy
- Geothermal Energy
- Gravitational Potential Energy
- Heat Engines
- Heat Transfer Efficiency
- Kinetic Energy
- Mechanical Power
- Potential Energy
- Potential Energy and Energy Conservation
- Pulling Force
- Renewable Energy Sources
- Wind Energy
- Work Energy Principle
- Engineering Physics
- Angular Momentum
- Angular Work and Power
- Engine Cycles
- First Law of Thermodynamics
- Moment of Inertia
- Non-Flow Processes
- PV Diagrams
- Reversed Heat Engines
- Rotational Kinetic Energy
- Second Law and Engines
- Thermodynamics and Engines
- Torque and Angular Acceleration
- Famous Physicists
- Fields in Physics
- Alternating Currents
- Capacitance
- Capacitor Charge
- Capacitor Discharge
- Coulomb's Law
- Electric Field Strength
- Electric Fields
- Electric Potential
- Electromagnetic Induction
- Energy Stored by a Capacitor
- Equipotential Surface
- Escape Velocity
- Gravitational Field Strength
- Gravitational Fields
- Gravitational Potential
- Magnetic Fields
- Magnetic Flux Density
- Magnetic Flux and Magnetic Flux Linkage
- Moving Charges in a Magnetic Field
- Newton’s Laws
- Operation of a Transformer
- Parallel Plate Capacitor
- Planetary Orbits
- Synchronous Orbits
- Fluids
- Absolute Pressure and Gauge Pressure
- Application of Bernoulli's Equation
- Archimedes' Principle
- Conservation of Energy in Fluids
- Fluid Flow
- Fluid Systems
- Force and Pressure
- Force
- Conservation of Momentum
- Contact Forces
- Elastic Forces
- Force and Motion
- Gravity
- Impact Forces
- Moment Physics
- Moments Levers and Gears
- Moments and Equilibrium
- Pressure
- Resultant Force
- Safety First
- Time Speed and Distance
- Velocity and Acceleration
- Work Done
- Fundamentals of Physics
- Further Mechanics and Thermal Physics
- Bottle Rocket
- Charles law
- Circular Motion
- Diesel Cycle
- Gas Laws
- Heat Transfer
- Heat Transfer Experiments
- Ideal Gas Model
- Ideal Gases
- Kinetic Theory of Gases
- Models of Gas Behaviour
- Newton's Law of Cooling
- Periodic Motion
- Rankine Cycle
- Resonance
- Simple Harmonic Motion
- Simple Harmonic Motion Energy
- Temperature
- Thermal Equilibrium
- Thermal Expansion
- Thermal Physics
- Volume
- Work in Thermodynamics
- Geometrical and Physical Optics
- Kinematics Physics
- Air Resistance
- Angular Kinematic Equations
- Average Velocity and Acceleration
- Displacement, Time and Average Velocity
- Frame of Reference
- Free Falling Object
- Kinematic Equations
- Motion in One Dimension
- Motion in Two Dimensions
- Rotational Motion
- Uniformly Accelerated Motion
- Linear Momentum
- Magnetism
- Ampere force
- Earth's Magnetic Field
- Fleming's Left Hand Rule
- Induced Potential
- Magnetic Forces and Fields
- Motor Effect
- Particles in Magnetic Fields
- Permanent and Induced Magnetism
- Magnetism and Electromagnetic Induction
- Eddy Current
- Faraday's Law
- Induced Currents
- Inductance
- LC Circuit
- Lenz's Law
- Magnetic Field of a Current-Carrying Wire
- Magnetic Flux
- Magnetic Materials
- Monopole vs Dipole
- RL Circuit
- Measurements
- Mechanics and Materials
- Acceleration Due to Gravity
- Bouncing Ball Example
- Bulk Properties of Solids
- Centre of Mass
- Collisions and Momentum Conservation
- Conservation of Energy
- Density
- Elastic Collisions
- Force Energy
- Friction
- Graphs of Motion
- Linear Motion
- Materials
- Materials Energy
- Moments
- Momentum
- Power and Efficiency
- Projectile Motion
- Scalar and Vector
- Terminal Velocity
- Vector Problems
- Work and Energy
- Young's Modulus
- Medical Physics
- Absorption of X-Rays
- CT Scanners
- Defects of Vision
- Defects of Vision and Their Correction
- Diagnostic X-Rays
- Effective Half Life
- Electrocardiography
- Fibre Optics and Endoscopy
- Gamma Camera
- Hearing Defects
- High Energy X-Rays
- Lenses
- Magnetic Resonance Imaging
- Noise Sensitivity
- Non Ionising Imaging
- Physics of Vision
- Physics of the Ear
- Physics of the Eye
- Radioactive Implants
- Radionuclide Imaging Techniques
- Radionuclide Imaging and Therapy
- Structure of the Ear
- Ultrasound Imaging
- X-Ray Image Processing
- X-Ray Imaging
- Modern Physics
- Bohr Model of the Atom
- Disintegration Energy
- Franck Hertz Experiment
- Mass Energy Equivalence
- Nuclear Reaction
- Nucleus Structure
- Quantization of Energy
- Spectral Lines
- The Discovery of the Atom
- Wave Function
- Nuclear Physics
- Alpha Beta and Gamma Radiation
- Binding Energy
- Half Life
- Induced Fission
- Mass and Energy
- Nuclear Instability
- Nuclear Radius
- Radioactive Decay
- Radioactivity
- Rutherford Scattering
- Safety of Nuclear Reactors
- Oscillations
- Energy Time Graph
- Energy in Simple Harmonic Motion
- Hooke's Law
- Kinetic Energy in Simple Harmonic Motion
- Mechanical Energy in Simple Harmonic Motion
- Pendulum
- Period of Pendulum
- Period, Frequency and Amplitude
- Phase Angle
- Physical Pendulum
- Restoring Force
- Simple Pendulum
- Spring-Block Oscillator
- Torsional Pendulum
- Velocity
- Particle Model of Matter
- Physical Quantities and Units
- Converting Units
- Physical Quantities
- SI Prefixes
- Standard Form Physics
- Units Physics
- Use of SI Units
- Physics of Motion
- Acceleration
- Angular Acceleration
- Angular Displacement
- Angular Velocity
- Centrifugal Force
- Centripetal Force
- Displacement
- Equilibrium
- Forces of Nature Physics
- Galileo's Leaning Tower of Pisa Experiment
- Inclined Plane
- Inertia
- Mass in Physics
- Speed Physics
- Static Equilibrium
- Radiation
- Antiparticles
- Antiquark
- Atomic Model
- Classification of Particles
- Collisions of Electrons with Atoms
- Conservation Laws
- Electromagnetic Radiation and Quantum Phenomena
- Isotopes
- Neutron Number
- Particles
- Photons
- Protons
- Quark Physics
- Specific Charge
- The Photoelectric Effect
- Wave-Particle Duality
- Rotational Dynamics
- Angular Impulse
- Angular Kinematics
- Angular Motion and Linear Motion
- Connecting Linear and Rotational Motion
- Orbital Trajectory
- Rotational Equilibrium
- Rotational Inertia
- Satellite Orbits
- Third Law of Kepler
- Scientific Method Physics
- Data Collection
- Data Representation
- Drawing Conclusions
- Equations in Physics
- Uncertainties and Evaluations
- Space Physics
- Thermodynamics
- Heat Radiation
- Thermal Conductivity
- Thermal Efficiency
- Thermodynamic Diagram
- Thermodynamic Force
- Thermodynamic and Kinetic Control
- Torque and Rotational Motion
- Centripetal Acceleration and Centripetal Force
- Conservation of Angular Momentum
- Force and Torque
- Muscle Torque
- Newton's Second Law in Angular Form
- Simple Machines
- Unbalanced Torque
- Translational Dynamics
- Centripetal Force and Velocity
- Critical Speed
- Free Fall and Terminal Velocity
- Gravitational Acceleration
- Kinetic Friction
- Object in Equilibrium
- Orbital Period
- Resistive Force
- Spring Force
- Static Friction
- Turning Points in Physics
- Cathode Rays
- Discovery of the Electron
- Einstein's Theory of Special Relativity
- Electromagnetic Waves
- Electron Microscopes
- Electron Specific Charge
- Length Contraction
- Michelson-Morley Experiment
- Millikan's Experiment
- Newton's and Huygens' Theories of Light
- Photoelectricity
- Relativistic Mass and Energy
- Special Relativity
- Thermionic Electron Emission
- Time Dilation
- Wave Particle Duality of Light
- Waves Physics
- Acoustics
- Applications of Ultrasound
- Applications of Waves
- Diffraction
- Diffraction Gratings
- Doppler Effect in Light
- Earthquake Shock Waves
- Echolocation
- Image Formation by Lenses
- Interference
- Light
- Longitudinal Wave
- Longitudinal and Transverse Waves
- Mirror
- Oscilloscope
- Phase Difference
- Polarisation
- Progressive Waves
- Properties of Waves
- Ray Diagrams
- Ray Tracing Mirrors
- Reflection
- Refraction
- Refraction at a Plane Surface
- Resonance in Sound Waves
- Seismic Waves
- Snell's law
- Spectral Colour
- Standing Waves
- Stationary Waves
- Total Internal Reflection in Optical Fibre
- Transverse Wave
- Ultrasound
- Wave Characteristics
- Wave Speed
- Waves in Communication
- X-rays
- Work Energy and Power
- Conservative Forces and Potential Energy
- Dissipative Force
- Energy Dissipation
- Energy in Pendulum
- Force and Potential Energy
- Force vs. Position Graph
- Orbiting Objects
- Potential Energy Graphs and Motion
- Spring Potential Energy
- Total Mechanical Energy
- Translational Kinetic Energy
- Work Energy Theorem
- Work and Kinetic Energy

Lerne mit deinen Freunden und bleibe auf dem richtigen Kurs mit deinen persönlichen Lernstatistiken

Jetzt kostenlos anmeldenNie wieder prokastinieren mit unseren Lernerinnerungen.

Jetzt kostenlos anmeldenThe capacitance of a capacitor is measured in Farad and is the amount of energy it can store. Capacitors are used as crucial components of electrical circuits in many modern devices, including pacemakers, mobile phones, and computers.

Capacitors are commonly used to store electrical energy and release it when needed. They typically feature in combination with other circuit components to produce a filter that allows some electrical impulses to pass while blocking others.

Capacitors have two conductive plates separated by an insulator material. When the capacitor is charging, the following two steps below occur in the order in which they are listed:

- A
**potential****difference**between the two conductive plates begins to rise as a result of the electrical field created by the source in the circuit. One of the plates gains excess electrons from the other plate because the electrical field of the source is pushing the electrons from the plate whose positive pole is directed towards. - Once the charging is completed, one of the plates has a positive charge, while the other has a negative charge.

When the capacitor is discharging, the electron excess on the negatively charged plate starts to flow to the positively charged plate, which causes the capacitor to create an **electron ****flow **in the circuit and act as a voltage source for a period of time. This electron flow stops when the potential difference between the plates comes down to zero, which means that both plates are neutral at that point, and the charge that the capacitor was holding has been given back to the circuit.

A capacitator’s discharge behaviour depends on whether it is found in an AC or a DC circuit.

In DC circuits, the capacitor charges and discharges only once. To understand the concept better, take a look at the circuit below.

In this circuit, the ammeter (A) indicates the value of current flowing through the capacitor, while the voltmeter (V) indicates the potential difference between the plates. When we move the switch to position 1, the capacitor charges. The upper plate is charged positively because the **electric field **of the source pushed the electrons in the upper plate into the bottom plate, which means that the bottom plate is charged negatively. If we then move the switch to position 3**,** the capacitor begins to discharge.

Right after we move the switch to position 3, electron flow from the capacitor starts. Since it is in the opposite direction to the electron flow that was happening when the capacitor was charging, the ammeter’s indicator for a short time turns in the opposite direction before going back to zero. This load flow ends when the charge of the two plates of the capacitor is at the same level, which indicates that the capacitor has discharged.

Since the capacitor in the circuit in Figure 2 is **short-circuited**, the time period while the electron flow is present is very short. To increase this time period and use the capacitor as a source for a longer time, **resistors **need to be connected to the circuit since they resist current flow.

In the figure above**, **Vc** **is the voltage value of the capacitor, V

As you can see, in DC circuits, we speak of the **temporary state **when the capacitor is discharging and the voltage level goes down to zero. When the capacitor is fully discharged, we speak of the **steady state**. This is the main difference between how capacitors behave in DC and AC circuits.

In this figure, Ic is the current flowing through the capacitor, -V/R is the value of the current flowing through the capacitor when it is fully charged, and t** **is time.

You can see that the value of the current is starting to reach zero from a negative value. This is because the electron flow is in the opposite direction to the direction it was while the capacitor was charging. The direction of the current flow is, of course, also different.

After the capacitor is discharged, unless we move the switch to position 1, the charge of the capacitor and the current going through the circuit will remain zero.

Whereas a capacitator in a DC circuit discharges only once, in an AC circuit, it **charges and discharges continuously**. The current flow is also different compared to a DC circuit, where it flows in one direction until the capacitor is discharged and then stops. In an AC circuit, by contrast, **current flows in both directions **continuously.

In this figure, V(t) is the voltage depending on time, i(t) is the current depending on time, V_{m} is the peak value of the voltage of the capacitor, I_{m}** **is the peak value of the alternative current going through the capacitor, and θ is the phase difference between the voltage and the current of the capacitor.

To understand the concept better, we will look at it in different parts of a period. Normally, there are four parts where the capacitor behaves differently: 0-π / 2, π / 2-π, π -3π / 2, and 3π / 2-2π. Let’s say the phase angle is a. In the π/2<a<π and the 3π/2<a<2π periods, the capacitor is discharging while in the other two periods, it is charging.

As you can see in figure 6, at a = π/2, the current is zero, and the capacitor’s voltage is at its maximum value (V = V_{m}). This also indicates that the load on the capacitor is at its maximum: \(q = Q_m = V_m \cdot C\), where q is the load, Q_{m} is the maximum load, V_{m} is the peak value of the AC source, and C is capacitance.

In this figure,** **Vt is the AC voltage source, which depends on time, while \(V_{max} \cdot \sin(\omega t)\) is the function defining its sinusoidal behaviour.

Because the voltage value of the AC source is decreasing after a=π/2, the capacitor’s voltage will decrease as well. This also implies that the capacitor’s load will decrease, forcing the **electron flow to reverse direction**** **as the excess electrons in the bottom plate go to the upper plate. That is the reason why the current’s direction changes. As we get closer to a=π, the voltage of the AC source begins to change rapidly, causing the current value to rise. The capacitor’s voltage value is 0 at the a=π point, indicating that it has discharged.

Because the capacitor’s voltage is at its peak at the a**=**3π/2 point, the load will be at its maximum as well. And because the capacitor is completely charged, there will be no current flowing through it at this precise moment. As a result, the current value is i = 0.

Notice how the bottom plate of the capacitor is now charged. This is because in the π <a** **<3π/2 period, the current that the AC source generates was flowing in the opposite direction, causing the capacitor to charge in the opposite direction.

The voltage of the source decreases after a=3π/2, implying that the voltage of the capacitor will drop as well, and the capacitor will begin to discharge. As we get closer to the 2π point, the rate of change of the voltage (dV/dt) and the current both increase.

The value of the **current is at its maximum **at point 2π, and the value of the AC source voltage is zero. The load on the capacitor (q) is also 0 at this moment since it has been discharged.

When a basic circuit like the one we just studied doesn’t include a resistor, it is impossible to calculate the time it takes a capacitor to discharge. However, there is no need to calculate it because the capacitator will discharge very quickly. So, to calculate the time it takes a capacitor to discharge, we need an **RC **circuit. Let’s consider the example below.

In the circuit below, the capacitor is fully charged with 10 volts. If we close the switch at time t = 0, how much time will it take for the capacitor to fully discharge?

The time it takes for the capacitor to discharge is 5T, where T is the time constant that can be calculated as:

\[\tau = R \cdot C\]

Entering the known values, we get:

\[\tau = 100[\Omega] \cdot 0.02[F] = 2[s]\]

And, as already said, the discharge time equals 5T. This gives us:

\[5 \cdot \tau = 2[s]\cdot 5 = 10 [s]\]

- There is a difference in how capacitors operate in DC and AC circuits since the voltage levels are steady in DC and constantly changing in AC.
- Capacitator discharge happens when the electric field of the source surrounding the capacitor disappears, causing the start of the electron flow from the conductive plates to the circuit.
- The time it takes for a capacitor to discharge is 5T, where T is the time constant.
- There is a need for a resistor in the circuit in order to calculate the time it takes for a capacitor to discharge, as it will discharge very quickly when there is no resistance in the circuit.
- In DC circuits, there are two states when a capacitor is discharging. The first is the temporary state, which is while the capacitor is discharging. The second is the steady state, which is when the capacitor is fully discharged.

The time it takes for a capacitor to discharge is 5T, where T is the time constant.

More about Capacitor Discharge

How would you like to learn this content?

Creating flashcards

Studying with content from your peer

Taking a short quiz

94% of StudySmarter users achieve better grades.

Sign up for free!94% of StudySmarter users achieve better grades.

Sign up for free!How would you like to learn this content?

Creating flashcards

Studying with content from your peer

Taking a short quiz

Free physics cheat sheet!

Everything you need to know on . A perfect summary so you can easily remember everything.

Be perfectly prepared on time with an individual plan.

Test your knowledge with gamified quizzes.

Create and find flashcards in record time.

Create beautiful notes faster than ever before.

Have all your study materials in one place.

Upload unlimited documents and save them online.

Identify your study strength and weaknesses.

Set individual study goals and earn points reaching them.

Stop procrastinating with our study reminders.

Earn points, unlock badges and level up while studying.

Create flashcards in notes completely automatically.

Create the most beautiful study materials using our templates.

Sign up to highlight and take notes. It’s 100% free.