what a 1:1 choke balum used for
On Tue, 28 Mar 2006 12:59:52 -0500, John Popelish
wrote:
With this in mind, do we add a characteristic of loss to the
definition? A lossy air core transformer with series driven, bucking
sections.
Air core? It is a ferrite core transformer with two one turn
Hi John,
If there's a transformer in the sense of windings; then it is an air
core, the ferrite is wholly transparent to the transverse currents.
You could remove the ferrite and it wouldn't make a bit of difference
in that sense of transforming.
this current mismatch would cause the transformer to
produce more or less voltage across the windings
In fact, nothing of that sort happens - at least not by your
description. The ferrite is simply bulk resistance inserted into the
common mode path. That is why common mode current is suppressed. The
same thing occurs in the coiled transmission line choke, but the
resistance is replaced by reactance. Again, common mode current is
snubbed by encountering this too.
The transformer property is in the isolation of the balanced circuit
from the unbalanced circuit through this resistive characteristic.
You are missing one path. The two from the source in the form of the
inner shield of the coax, and the center conductor, and the one from
the load in the form of the outer shield of the coax (same shield, but
isolated circuits). Further, there is no flux linkage of the two
conductors coming from the source. Their magnetic lines never break
the cores, whereas the common mode current does break the core which
thus inserts the resistance of the ferrite.
73's
Richard Clark, KB7QHC
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