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Old 28th November 2010, 07:08 PM   #911
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In the first time baby huey thread, gingertube says connect a 10ohm resistor from a 12v supply to the positive bias side, to check the circuit. You should read 0.4v across the resistor for 40mA current.

I am testing my circuit using the CCS winding (5v 3A) and a 470ohm resistor.

I read 5.28v across the resistor, ohms law tells me that's about 11mA current.

All 4 of my bias circuits read the same, so unless ive built all 4 wrong... I must be doing something else wrong...?

Can anyone help?

Thanks

Charlie

Still learning
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Old 28th November 2010, 07:36 PM   #912
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Apologies in advance for stating the obvious, but you need dc and it may be unreliable to use less than 12v


Bill
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Old 28th November 2010, 07:41 PM   #913
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Ah.. yes.... that would be it then.

Think ill put this to bed for today and have a glass of wine
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Old 28th November 2010, 07:44 PM   #914
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My trouble is after the third glass I feel like going back to work

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Old 28th November 2010, 08:03 PM   #915
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I just quickly checked with a 9v battery, read about 15mA.

Should I just continue with the build and check again when everything is in place? As I dont have a workshop power supply to get the 12v DC

Charlie
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Old 28th November 2010, 08:10 PM   #916
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I used the -dc output from the voltage doubler needed for the ccs, it was about -13vdc IIRC.

ps how many glasses did you have..
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Old 28th November 2010, 08:14 PM   #917
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its a very nice Rioja....
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Old 28th November 2010, 08:18 PM   #918
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The last time I had a bottle of red I went on diyaudio and got myself "moderated"

They're very understanding here

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Old 28th November 2010, 09:00 PM   #919
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OK..

10.4V across 470ohm, 22mA..... getting closer
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Old 28th November 2010, 09:10 PM   #920
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So that's with a 12v supply..

why I am getting half the current I should have? ..any more school boy mistakes I might of made?
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