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Confusing behavior in LCR/stepup transformer circuit - Help?
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me_engineer:
I did this measurement:
Open circuit output - 2.29Vrms
15 ohms output - 2.25Vrms
5 ohms output - 2.16Vrms
Z = ( R1 - R1*(V1/V2) ) / ( V1/V2 - R1/R2 )
(15-15*(2.25/2.16))/(2.25/2.16-15/5) = 0.32 ohms.

This is nowhere near enough impedance to explain the discrepancy. 

Perhaps there is a large reactance of some sort as well in the amplifier output?  It's Class H, which I don't think has any kind of output transformer or anything?  But I don't know the internals.

Maybe someone could verify that I'm measuring my transformer correctly?

Thanks for all the help!
iMo:
Does an inexpensive audio amplifier work till 50-70kHz flat?
me_engineer:
Not really that flat, but flat enough for these purposes.

The two features that are really confusing is the lack of improved efficiency (a dip in current) at resonance, which is absent in the physical version, and the current trend vs. frequency is opposite of what the simulation predicts.
radiolistener:
your transformer has 1:100 impedance ratio transformation (1:10 turns ratio).
What do you expect from this circuit on the output?
R3 is your output?

Did you check whats going on for entire 0...300 kHz range?

T3sl4co1l:
Output impedance should be factored out due to measuring the source voltage and calculating gain from that point.

What is this component?  Is there any way for us to check that your LCR measurements are correct?

Tim
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