Converting VAC to VDC

Discussion in 'General Electronics Chat' started by thakid87, Oct 2, 2009.

  1. thakid87

    thakid87 Thread Starter Active Member

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    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
  2. gerty

    gerty Well-Known Member

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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
  3. thakid87

    thakid87 Thread Starter Active Member

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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.
  4. beenthere

    beenthere Retired Moderator

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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.
  5. thakid87

    thakid87 Thread Starter Active Member

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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: Oct 2, 2009
  6. gerty

    gerty Well-Known Member

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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.
  7. thakid87

    thakid87 Thread Starter Active Member

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    Sorry, I'll try and be more specific in the future.
  8. StayatHomeElectronics

    StayatHomeElectronics Well-Known Member

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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.
  9. thakid87

    thakid87 Thread Starter Active Member

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    6-8A max current. I appreciate the help guys.
  10. steinar96

    steinar96 Active Member

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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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