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  #1  
Old 10-02-2009, 07:36 PM
thakid87 thakid87 is offline
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Default Converting VAC to VDC

Hello all.

Very easy question...

Is there a component that would convert vac to vdc that is small enough to mount on a PCB board?

Thanks,
Alex
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  #2  
Old 10-02-2009, 07:41 PM
gerty gerty is offline
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A diode or bridge rectifier will do what you want.
If you gave us more information we can reccomend a part number for you.
Wwhat is the voltage
What is the current
Do you need half wave or full wave rectification
Do you need filtering
Do you need regulating
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  #3  
Old 10-02-2009, 07:45 PM
thakid87 thakid87 is offline
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Voltage in would be mains voltage at 240VAC, not sure what the current is rated at. I would like to step it down to 24VDC. Filtering and regulation are definite pluses, but not necessary.
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Old 10-02-2009, 07:52 PM
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beenthere beenthere is offline
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Then you need an intermediate device - a step down transformer. It will reduce the voltage and isolate you from the mains. The load current is quite significant for the proper selection of the transformer, though.
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  #5  
Old 10-02-2009, 07:56 PM
thakid87 thakid87 is offline
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I'm a little hesitant on doing this, but should I just plug my probes in there and try to measure current?

Actually now that I think about it, current must be measured in series. So, how do I go about measuring the current that my house receives? A clamp on meter? Is there any other to do this without a clamp on meter? I don't have access to one right now.

Last edited by thakid87; 10-02-2009 at 08:04 PM.
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  #6  
Old 10-02-2009, 08:02 PM
gerty gerty is offline
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Why don't you tell us exactly what it is you want to do?
In the first post you did not mention dropping the voltage down.
Always give all the details you can in the first post and it'll make giving you an answer so much easier.
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Old 10-02-2009, 08:05 PM
thakid87 thakid87 is offline
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Sorry, I'll try and be more specific in the future.
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  #8  
Old 10-02-2009, 08:24 PM
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StayatHomeElectronics StayatHomeElectronics is offline
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When beenthere is asking for the load current he is not asking for the current coming into your house but for the current required at the 24VDC end. What are you going to run on the 24VDC side and how much current does it require? The transformer can only be selected after these details are known.
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Old 10-02-2009, 08:34 PM
thakid87 thakid87 is offline
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6-8A max current. I appreciate the help guys.
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  #10  
Old 10-02-2009, 10:59 PM
steinar96 steinar96 is offline
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Then you need a transformer rated for ~250W.

At 8 amps/24 V you are drawing aprox 200W. So you need a transformer at least capable of that.

A diode bridge to rectify the AC signal and a capacitor for minimal regulation is probably also needed.
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