One word answers...
Owen Duffy wrote:
Lets escape from mixed analysis of VSWR in transient scenarios.
Visualise a series circuit of a battery of 100V and negligible internal
resistance, a 100 ohm ideal resistor, and an open switch. This circuit is
connected to a lossless (ie ideal) transmission line with surge impedance
(or characteristic impedance, Zo) of 100 ohms which is open circuit at
the far end. It takes T seconds for a wave to travel from one end of the
line to the other.
At precisely t=2T seconds, the reflected wave reaches the source end of
the line, and the voltage at the line terminals instantly becomes Vf+Vr
or 100V. At that instant, the current from the source falls to zero, and
the dissipation in the source resistor also falls to zero. This situation
continues indefinitely.
My questions a
How much of the energy that was contained in the reflected wave was
dissipated in the source resistor?
None.
Does existence of a reflected wave necessarily increase dissipation in
the equivalent source resistance?
No.
Is the reflected wave necessarily absorbed (or partly absorbed) by the
equivalent source resistance?
No.
Are the principles that apply to this example inconsistent with the
general case (eg dc, ac, transient, steady state etc)?
Yes.
One word answers should be sufficient.
Ok.
Owen
Best,
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