In alt.engineering.electrical VWWall wrote:

| Actually, a real current will flow until the line's capacitance is
| charged to the source voltage. When the source is removed, the energy
| involved will remain until it is leaked off through the inter-wire
| resistance. If the source is AC, no net energy will "flow", except that
| lost in the inter-wire resistance. If the line length is long enough at
| the frequency involved, reflections from the end of an incorrectly
| terminated transmission line will return to dissipate energy in the
| source resistance.

That reflection even happens with DC. When the switch closes, you have a
rising wavefront leading the chargeup of the line. Unless the far end has
a perfectly matched load, that wavefront will reflect back. This is in
fact how a lot of very early radio transmissions were tuned, with the
"switch" being a noisy spark gap, and the "line" being a long wire antenna
cut to a specific length. You don't even need to have 2 conductors.


| --
| Virg Wall, P.E.
| K6EVE

They seem to not believe me because I am a "mere amateur". You might suffer
the same fate from some of them (I won't name names; it's not hard to figure
out who they are).

--
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| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |