Lecture 2 example, LC circuitTutorialCurrent spec2:210 min

ENGR5001 Lecture 2 worked example 2, LC circuit (slides 9-14)

For the LC circuit in the figure (an inductor LL in series with a capacitor CC, input voltage ViV_i applied across the pair, output voltage VoV_o taken across the capacitor, loop current ii):

LC circuit: inductor L in series with capacitor C, input V_i, output V_o across C, loop current i.
LC circuit: inductor L in series with capacitor C, input V_i, output V_o across C, loop current i.
Formulas you may need
  • Inductor VL=LdidtV_L = L\dfrac{di}{dt}; capacitor VC=qC=1C∫i dtV_C = \dfrac{q}{C} = \dfrac{1}{C}\displaystyle\int i\,dt; Kirchhoff's voltage law (learn this)
  • Generalised second order form d2xdt2+2ζωndxdt+ωn2x=Ku(t)\dfrac{d^2x}{dt^2} + 2\zeta\omega_n\dfrac{dx}{dt} + \omega_n^2 x = Ku(t) (learn this)
  1. (a)
    State the assumptions.
  2. (b)
    Develop the linear model relating ViV_i to VoV_o.
  3. (c)
    Convert the model into the generalised form and identify the input, output, KK, natural frequency, damping ratio and steady state gain. Which mechanical model has the same form?