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reading schematic - power source

Discussion in 'Electronic Repair' started by ll, Jun 22, 2007.

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  1. ll

    ll Guest

    I have a schematic showing connections from a transformer to a circuit
    board. Each connection reads: "12.6VAC" followed by the connection id
    (in this case "TP7" and TP8"). My question is: would the transformer
    in this situation be called a 12.6VAC transformer, or would these
    voltage markings on the schematic indicate the voltage for each

    This came up recently when I was looking for a replacement trans
    online, and the transformer, rated at 12.6VAC had markings on its
    underside that said "6.3V, 0V, 6.3V".

    Thanks for any leads,
  2. If the transformer is centre tapped and that connected I'd expect it to be
    12.6v per winding. Usually to provide a symmetrical power supply.

    It's common these days to have two separate windings on replacement type
    or general purpose transformers. That gives the maximum flexibility of
  3. ll

    ll Guest

    Thanks Dave,
    Do you think that the transformer with the markings may have indeed
    been a 6.3V one?
  4. DaveM

    DaveM Guest

    Are you saying that the original transformer has those markings (6.3V, 0V,
    6.3V)? If so, then it's a 12.6V center tapped transformer. That is, there are
    6.3V on either side of the center tap, for a total of 12.6V.
    If your schematic doesn't show a 0V terminal (which would be the connection for
    the center tap), then it just needs a transformer with a single 12.6V secondary.
    Your replacement transformer will work just fine; just don't connect the center
    tap terminal (0V) to anything.
    All the above presupposes that the current rating of the replacement transformer
    is sufficient for the application. If the replacement transformer and the
    original are very close to the same size and weight, then it's likely that it
    will work nicely.

    Dave M
    MasonDG44 at comcast dot net (Just substitute the appropriate characters in the

    "In theory, there isn't any difference between theory and practice. In
    practice, there is." - Yogi Berra
  5. ll

    ll Guest

    Many thanks for your input and help in this.
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