Convert 120v AC to 120v DC

Discussion in 'The Projects Forum' started by MiscLife, Feb 13, 2010.

  1. MiscLife

    Thread Starter New Member

    Feb 13, 2010
    2
    0
    Hi,

    I'm planning on putting together something that converts line 120v AC to 120v DC @ 5A or so. What parts would I need in addition to a bridge recitifier and a heat sink?
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    You must plan on using a transformer. A secondary voltage of 80 - 90 volts will put you in the "or so" range - rectified and filtered DC is about 1.4 times the RMS voltage rating.

    What's the heat sink for?
     
  3. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    After the bridge rectifier use a capacitor filter ans then a buck DC-DC converter to regulate the voltage to 120V DC. A transformer is not really required unless you want isolation from the mains or to obtain a better efficiency of the converter.
     
  4. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,348
    Hello,

    I think the use of a transformer is a must.
    Either in a normal way like beenthere said or in a SMPS powersupply.
    A transformer will provide a certain safety for you and others.

    Greetings,
    Bertus
     
  5. MiscLife

    Thread Starter New Member

    Feb 13, 2010
    2
    0
    Can the circuit be isolated without the use of a transformer? What if a circuit breaker is used before the power is connected to the main?
     
  6. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    That does not provide any isolation. If a circuit is fed directly from the line, it is all too possible for someone touching any part of that circuit to become a current path from the line to ground, resulting in a fatal shock.

    For that matter, working with a properly isolated DC voltage as high as 120 volts also presents a lethal shock hazard. We would discourage working with such voltages until you have a level of experience working with circuits that lets you know how to manage things safely. Any accidental contact with a live terminal can be deadly.

    What are you trying to do?
     
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