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simonwai999
Joined: 30 Jun 2008
Posts: 113
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 17 Aug 2008 14:48 power transformer questions |
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hi folks
in my city we use 220vac
i have a power transformer
220 primary and 9-0-9 secondary
all i need is 9vdc
can i connected (9-0)-9 the 2 pins in the bracket to get 9vac then rectify it
to 9vDC for the 7805 ic?
thanks
http://www.edaboard.com/viewtopic.php?p=631388#631388
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kiprono
Joined: 18 Nov 2005
Posts: 243
Helped: 15
Location: Nairobi
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| 17 Aug 2008 16:06 Re: power transformer questions |
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| You are right. Your transformer has a centre - tapped secondary.
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tonybg
Joined: 17 Mar 2007
Posts: 16
Helped: 2
Location: bulgaria
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| 17 Aug 2008 17:12 Re: power transformer questions |
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yes, you can get DC from the secondary coil.But it is a little bit different.Use the 0 for (-) on the DC side.Then on the two 9Vac ends connect two diodes-anode to the AC side and cathode to DC side(connected together). Don't forget the electrolitic capacitor.You will measure DC voltage more than 9volts.But you will need at least 2volts difference inorder for 7805 to stabilize.Be careful what current you draw from 7805.If it is more than 200mA use aluminium plate to cool the device.Don't forget
HELPED ME!
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simonwai999
Joined: 30 Jun 2008
Posts: 113
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| 17 Aug 2008 17:14 Re: power transformer questions |
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hi
thanks for your fast reply
ciao
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