reading schematic - power source

Jun 22, 2007 4 Replies
L

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 lead?



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, Louis



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D

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 connection.

Small asylum seeker wanted as mud flap, must be flexible and willing to travel Dave Plowman dave@davenoise.co.uk London SW To e-mail, change noise into sound.
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L

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

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D

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 address) "In theory, there isn't any difference between theory and practice. In practice, there is." - Yogi Berra
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L

secondary.

transformer

the

Dave, Many thanks for your input and help in this. Louis

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