- #1
- 2
- 0
I was wondering, at high frequency circuits, when the lumped circuit model must be used, why does impedance depends on the position in the wire?
By the way, it's my very first post here =D
By the way, it's my very first post here =D
But why impedance oscillates? I understand how resistance is affected, but following this logic, capacitance and inductance should also increase with distance, but they don't, they vary sinusoidally.Many many things that are not significant at low frequencies become so at high frequencies. When starting out with simple dry cells, resistors, light bulbs, etc. we certainly were not told that there is a small capacitance or inductance that affects the circuit at the brief instant we switch the power on or off. It is real though, but generally of no consequence so in order to avoid confusing new students it is not mentioned. When we come around to AC though, it may be significant and sometimes it is downright difficult to train our minds to consider these things that have been in front of us all along and we simply ignored.
I think you have some things confused. I don't understand what you mean by impedance oscillates. Nor do I understand what you mean by saying that capacitance and inductance vary sinusoidally. Capacitance is fixed. So is inductance. The reactance presented by each will vary with frequency but that is pretty much a linear relationship.But why impedance oscillates? I understand how resistance is affected, but following this logic, capacitance and inductance should also increase with distance, but they don't, they vary sinusoidally.
This OP is like “what happens when an irresistible force acts on an immovable mountain”. Either the circuit should not be modelled as “lumped constants”, or the frequency of interest should not be so “high”.I was wondering, at high frequency circuits, when the lumped circuit model must be used, why does impedance depends on the position in the wire?