RC Circuits

Textbook

• University Physics Volume 2: Chapter 8 - Capacitance
• University Physics Volume 2: Chapter 10.5 - RC Circuits

What is a Capacitor and what is Capacitance

Capacitor Discharge (Voltage over Time)

During the discharge of a capacitor through a resistor, the voltage decreases exponentially over time. $V(t)=V_{0}e^{-{\frac {t}{RC}}}$

• Where:*
• *V(t)* is the voltage at time t (in volts, V)
• *V_0* is the initial voltage (in volts, V)
• *R* is the resistance (in ohms, Ω)
• *C* is the capacitance (in farads, F)
• *t* is time (in seconds, s)

Capacitor Charging (Voltage over Time)

During charging, the voltage across a capacitor increases exponentially, approaching its final value. $V(t)=V_{0}\left(1-e^{-{\frac {t}{RC}}}\right)$

• Where:*
• *V(t)* is the voltage at time t (in volts, V)
• *V_0* is the final voltage (in volts, V)
• *R* is the resistance (in ohms, Ω)
• *C* is the capacitance (in farads, F)
• *t* is time (in seconds, s)

Videos

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Simulations

• Charging And Discharging A Capacitor
• An Example Of A Natural Capacitor
• Factors Affecting Capacitance
• PhET Capacitor Lab Simulations

Other Links

• Charged Parallel Plates
• RC circuit simulator