12vdc isolation

Discussion in 'General Electronics Chat' started by guyblom, Jun 7, 2015.

  1. guyblom

    Thread Starter New Member

    Jun 7, 2015
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    Hi All, it's been a while since I dabbled in electronics so I'm hoping for some advice. I have a 12vdc supply and I wish to create two 12vdc signals isolated from each other (from the one source). What is the easiest way to do this? Power isolator?

    Thanks
     
  2. blocco a spirale

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    Jun 18, 2008
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  3. guyblom

    Thread Starter New Member

    Jun 7, 2015
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    Thank you for your assistance!
     
  4. DickCappels

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    Aug 21, 2008
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    Use a transformer with dual secondaries.
     
  5. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    For DC?
     
    DickCappels likes this.
  6. Papabravo

    Expert

    Feb 24, 2006
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    I think you might want to clarify what you are trying to do. Your statements so far lead in at least three directions. Rather than guessing which of several directions you are going in why don't you provide additional information. What kind of signals are they for starters?
     
  7. ian field

    Distinguished Member

    Oct 27, 2012
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    If you can find some old PC EISA Ethernet cards, they used to have DC-DC converters on them - those won't do exactly what you want, but you can identify some brand names and go looking for manufacturers websites.

    I think the Ethernet ones were +/- 9V out from single 5V in, but most manufacturers do a complete range all the way up to 48V telecom stuff.
     
  8. guyblom

    Thread Starter New Member

    Jun 7, 2015
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    My apologies for being vague, I was unsure how much information to offer. I wish to run 2 lines (channels) of LED's each of which will be dimmed separately. I understand I would need two power sources isolated from each other but I only wish to use one supply/driver. This is obviously possible as many manufacturers do up to 4 separate channels from one power source.
     
  9. WBahn

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    Mar 31, 2012
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    Why do they need to be isolated from each other? I think the issue might be in your understanding of what electrical isolation means.

    Consider your car electrical system. You have 12V headlights and you have 12V brake lights that are turned on and off separately. Would you consider these two 12V lights to be "isolated" in the same way that you are looking for here?
     
  10. Papabravo

    Expert

    Feb 24, 2006
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    I suggest you review the material on series and parallel DC circuits. This will provide a framework for understanding how two separate branches of a circuit can be controlled.
     
  11. guyblom

    Thread Starter New Member

    Jun 7, 2015
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    I guess I foolishly listened to some "backyard" advice which suggested I needed isolated p/supply lines. Thank you to all who contributed - I shall go and research a little harder and return when I have more informed questions if that's ok.
     
  12. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    Dimming two LED strings independently does imply some kind of power isolation between them so they don't interact, but full isolation is not required for the task the way you have described it so far. From the 12 V source, two independent switching or linear regulators will do what you want. What is the peak current in each string at full brightness?

    ak
     
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