Physics · University
Capacitors, RC transients and field energy · revision notes
For a linear capacitor Q=CV, with stored energy CV²/2. Potential difference and capacitance must refer to the same device.
Key ideas and conditions
Capacitance
For a linear capacitor Q=CV, with stored energy CV²/2. Potential difference and capacitance must refer to the same device.
Time constant
An ideal RC discharge follows V(t)=V0 exp(−t/RC). The time constant is RC; discharge is asymptotic rather than abruptly complete.
Energy balance
Current through a resistor converts stored electrical energy into thermal energy. A transient circuit must respect both charge and energy accounting.
Limits
Ideal elements omit leakage, parasitic inductance and voltage-dependent effects. Numerical exercises state the idealization rather than promising device behaviour.
Explain without looking
- For a 10 V ideal discharge, find voltage at t=0.
- Describe a check that can catch a wrong sign in a discharge exponent.
Further reading and review references
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
AI-assisted preview; independent educational review required. Level labels describe prerequisites, not accreditation or official curriculum alignment.