Topband: T-200 vs. T-300

Paul Christensen w9ac at arrl.net
Thu Dec 15 07:49:31 PST 2011


> "A couple rules for toroidal inductors might be useful. To increase the 
> reactance you increase the number of turns -- the inductance goes up 
> approximately the square of the number of turns. To increase the power 
> handling capability you add additional cores to make a stack of cores. 
> This will also help with the inductance since the toroid core AL value is 
> affected by the cross sectional area of the core."

Another important rule when winding CM chokes:  On common-mode currents (the 
bad current), an inductance equal to 2*L is added in series with each of the 
two conductors.  On differential mode currents (the good current), L cancels 
and has no effect.  Ever wonder why we can keep adding so much L in CM choke 
windings and it does not appreciably degrade differential-mode current and 
frequency response?

Paul, W9AC




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