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Old 22nd Jun 2018, 12:56 pm   #29
ms660
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Join Date: Apr 2011
Location: Cornwall, UK.
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Default Re: How do IF transformers work?

Quote:
Originally Posted by kalee20 View Post
Lawrence is nearer, obviously he has a feel for the figures - coupling between the circuits is actually really low for critical response. I gave 10% only as an order-of-magnitude, and yes, typical 470kHz IFT's are often much less (though 10.7MHz ones, where Q's are lower, may approach 10%. But I've not yet designed one).
For what I said before, I just referred to an example in my book which was for something approaching a typical AM IF frequency, primary and secondary inductances and resistances were different but their Q's were the same so critical k=1/Q which happened to be k=0.01 (approx.)

Lawrence.
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