diode equivalent circuit

[Yuya_O]

This is about equivalent circuit of diode.

I saw the topic about equivalent circuit of diode. It says depend on the value of the capacitance(impedance), the equivalent circuit is changed to Rs Cs or Rp Cp(I attached the picture above).
Someone could you explain about this principle ?

 

[d123]

Hi,

At a guess, and I don't know how to explain it but know what I'm trying to articulate, high Zc is because parallel RC at low(er) frequencies acts like an integrator (low pass) and low Zc is because the series capacitor is a short at high(er) frequencies so only Rs matters as the impedance, differentiator. Low frequency: Rs + Rp = full impedance and C is open circuit element, high frequency: Rs + C will be lower impedance as C is a short and path of least resistance from in to out compared to through Rs + Rp. Depends on value of diode C. Sorry for pathetic, unhelpful, dubious explanation.