- #1
SteDolan
- 14
- 0
Homework Statement
A capacitor of capacitance C is connected in parallel with a resistor of R ohms impedance. Calculate the size of the peak to peak voltage of the ripple produced relative to the peak output voltage Vp.
Homework Equations
Q=CV
dQ/dt = I
V=IR
Vc=Vpe-t/RC (am i allowed to use this in an AC circuit?)
or Vc=-jI/R[itex]\omega[/itex]C
V = Vpcos([itex]\omega[/itex]t)
The Attempt at a Solution
Voltage drop across the resistor is just:
V = Vpcos([itex]\omega[/itex]t)
Voltage drop across the capacitor can be aproximated to:
Vc=Vp(1-e-t/RC)
The alteration to the equation in 2 is to ensure the capacitor voltage is 0 at t=0.
At t=0
VR - Vc = Vp
at t=T/2 or at 1/f
VR - Vc = Vpe-1/fRC
The ripple voltage will be the difference between these two:
VRipple= Vp(1-e-/fRC)
Last edited by a moderator: