Jim,
Please see my last posting.
The differential-mode input voltage is not just _between_ the windings
of one balun, it is _across_ the windings. If there were no
differential-mode transformer action you could never generate 2V at the
output from V at the input. No matter what the load-balance situation,
you must always have the differential-mode voltage shared between the
two balun cores as shown in my Fig 2, and so there will always be flux
directly proportional to the differential mode input.
Quote from W8JI:
"Baluns that transform impedance to new values, like a 4:1 balun,
somehow must always have full transmission line differential voltage
across a winding. This means you have a winding with voltage across it
that is creating flux in a core."
73,
Steve G3TXQ
Jim Brown wrote:
>
> BUT -- the flux is proportional to the common mode current, and thanks to
> the 5K resistance coupled from the core (the #31 or #43 core around its
> broad resonance), there is very little common mode current, and thus very
> little flux. There IS differential current in both windings -- that's how
> power is coupled to the load -- but the differential component of current
> produces no flux.
>
> 73,
>
> Jim Brown K9YC
>
>
>
>
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