6.1.2 Charging and Discharging

• What is a capacitor?

  Stores electrical charge
• A capacitor charges when connected to a voltage source and discharges when disconnected.


  True
• Steps in the charging process of a capacitor

  1️⃣ Charge builds up on conductor plates

  2️⃣ Electric field is created between plates

  3️⃣ Voltage across the capacitor increases

  4️⃣ Capacitor charges until voltage equals source voltage
• What happens to the stored charge during discharging?

  It flows out
• Steps in the charging process of a capacitor

  1️⃣ Charge builds up on conductor plates

  2️⃣ Electric field is created between plates

  3️⃣ Voltage across the capacitor increases

  4️⃣ Capacitor charges until voltage equals source voltage
• What begins to build up on the conductor plates of a capacitor when connected to a voltage source?

  Charge
• A capacitor stops charging when the voltage across it equals the voltage of the source.


  True
• During discharging, stored charge flows out through a connected load such as a resistor.
• Steps in the discharging process of a capacitor

  1️⃣ Disconnect from voltage source

  2️⃣ Stored charge flows out through a load

  3️⃣ Electric field between plates dissipates

  4️⃣ Voltage across the capacitor decreases
• Steps to derive the charging and discharging equations for a capacitor

  1️⃣ Define the charging process

  2️⃣ Derive the charging equation

  3️⃣ Define the discharging process

  4️⃣ Derive the discharging equation
• The charging equation shows that voltage increases over time, while the discharging equation shows that voltage decreases over time.


  True
• When a capacitor is connected to a voltage source, it charges and stores energy.

  True
• What happens to the charge on a capacitor during charging?

  It builds up
• The electric field created during charging opposes further charge flow.

  True
• During discharging, the voltage across a capacitor decreases.


  True
• The voltage across a capacitor increases continuously during charging until it exceeds the source voltage.

  False
• As more charge accumulates on a capacitor, an electric field is created between the plates.
• Steps in the charging process of a capacitor

  1️⃣ Charge builds up on the conductor plates

  2️⃣ Electric field is created between the plates

  3️⃣ Electric field opposes further charge flow

  4️⃣ Voltage across the capacitor increases

  5️⃣ Charging stops when voltage equals source voltage
• What happens to the electric field between the capacitor plates during discharging?

  Weakens
• What is the equation for the voltage across a charging capacitor as a function of time?

  $V_{c} =$$V_{s}(1 - e^{ - t / RC})$
• The voltage across a discharging capacitor decreases exponentially over time.


  True
• When a charged capacitor is disconnected from the voltage source, the voltage across the capacitor decreases over time according to the equation: $V_{c} =$$V_{0} e^{ - t / RC}$
• In the charging process, the voltage across the capacitor increases over time, while in the discharging process, it decreases
• Steps in the charging process of a capacitor:

  1️⃣ Charge begins to build up on conductor plates

  2️⃣ An electric field is created between the plates

  3️⃣ The electric field opposes further charge flow

  4️⃣ Voltage across the capacitor increases

  5️⃣ Capacitor charges until voltage equals source
• The voltage across a capacitor increases during charging due to the opposing effect of the electric field.
• What happens to the electric field between the plates of a capacitor during discharging?

  It weakens
• What is the variable $V_{0}$ in the discharging equation $V_{c} =$$V_{0} e^{ - t / RC}$ ?


  Initial voltage
• How long does it take for a capacitor to discharge to 36.8% of its initial voltage?

  One time constant
• Match the capacitor application with its description:

  Timing Circuits ↔️ Controls intervals in devices

  Power Smoothing ↔️ Smoothes voltage variations

  Energy Storage ↔️ Stores and delivers energy

  Filtering ↔️ Blocks unwanted frequencies
• A capacitor stores charge and energy in an electric field.
• During charging, the voltage across a capacitor increases over time.
• The capacitor stops charging when its voltage equals the source voltage.
• During discharging, energy is released from the electric field.
• What is the role of an insulator in a capacitor?

  Separates conductors
• What opposes the flow of further charge in a charging capacitor?

  Electric field
• What is the first step in the discharging process of a capacitor?

  Disconnect from voltage source
• The voltage across a discharging capacitor decreases until it reaches zero.

  True
• In the charging equation, $V_{s}$ represents the voltage of the source.
• What does $V_{0}$ represent in the discharging equation?


  Initial voltage
• When a capacitor is connected to a voltage source, the voltage across the capacitor increases over time according to the equation: $V_{c} =$$V_{s}(1 - e^{ - t / RC})$