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No Clue Newby transformer question.

Discussion in 'Beginner Electronics' started by Dave., Sep 20, 2004.

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  1. Dave.

    Dave. Guest

    Hi, I`m a complete electrics novice and at the moment every thing I
    try doesn`t work. Even down to shorting a PC`s Power Supply Unit so
    that it`ll work without being connected to the motherboard, which
    concists of "simply" grounding the power wire with a paperclip,
    would`nt work for me. What I realy want to know, though, is; in what
    order do power supply-transformer-mains supply, go. I`m pretty sure
    that the mains supply (230v) goes straight to the transformer and then
    from the transformer to the powersupply (PCB with resistors, led`s
    etc)and from the powersupply to the amp/radio/computer......
    I have seen schematic drawings for this but I don`t understand them
    and I have looked all over for a diagram or photo but can`t find one.
    I am just looking for a plain english explination coupled with some
    photographs. Any help apreceiated.
  2. blah

    blah Guest

    A transformer either converts the voltage up or down or isolates the power
    supply from the AC line.

    So power transformers are hooked directly to the AC line yes
    After that comes the "circuit" of the power supply with things like
    A bridge rectifier, a BIG capacitor or capacitors, a voltage regulator etc
    Be VERY careful screwing with 220. It can kill you so fast it's not funny.
  3. Reason

    Reason Guest

    I believe today's computers don't use transformers anymore. They use an
    electronic power supply instead.
  4. crzndog

    crzndog Guest

    If you are talking about getting a PC Power supply to switch on (for hobby
    reasons or what [ie a cheap psu]) yo uwill need to do the following:

    if an ATX PSU, short pin 14 of the psu connecto to GND (one of the black
    leads). YOu may also need a dummy load between the +5V (Red cable) and GND
    (Black cable). Usually PC PSUs are switched mode powersupplies and require
    500mA minimum loading for them to work correctly. This means you'll need
    5V/.5A = 10ohms (wire wound since it'll be dissapating 2.5Watts).
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