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diyAudio Member
Join Date: Oct 2003
Location: The Netherlands
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Hi Blitz,
Sorry for this late reply; I was on a business trip last week.
The values you have measured do surprise me. Are you sure that your choke has a DC resistance of 2.2 Ohm? It seems much lower.
The voltage change going form the full choke to the center tap is only 1.5V, although the resistance has halved from 2.2 to 1.1 Ohm at 6Adc. I would expect a bigger change, around 6.6V. The choke is in both cases above the critical inductance, so the output DC voltage should be around 0.9Vac minus diodes drop minus Idc.Rdc.
I'm also puzzled about the last configuration. You mention an increase in ripple to 55mV although I would have expected a value below the 33mV of the second case, because of inductance doubling due to current in the other winding (other half choke).
I think the last configuration is still a choke input, it makes no difference whether the choke is in the +/-supply line or the ground.
It would be very interesting to measure the current peaks in all these cases by using a current probe or via a small series resistor and a floating scope (or differential scope).
Steven
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The Analog Art shows no sign of yielding to the Dodo's fate. The emergence and maturation of monolithic processing finesse has perhaps lagged a bit behind the growth of the Binary Business. But whereas digital precision is forever bounded by bits, there is no limit excepting Universal Hiss to the ultimate accuracy and functional variety of simple analog circuits. - Barry Gilbert, 1973
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24th March 2004, 09:37 PM
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