There ain't no positive on a transformer. All transformers are AC.

Wow I am on a role today!

Sheesh....So it wouldn't matter how I wire it up then I suppose. (The two wires on the secondary).

Please exuse me. I'm acting terribly dumb.

 

We all get struck occasionally with moments of looking really dumb. No problem.

 

There ain't no positive on a transformer. All transformers are AC.

So then there is a positive on transformers?

So there is no confusion. There is no positive or neutral or hot on a transformer.

 

Well fellas, I just wired it up, and it works well!

My multimeter is telling me 7.8VAC which is perfect for what I was intending to use it for.

I'm no longer afraid of AC.

Thanks to all.

 

Well fellas, I just wired it up, and it works well!

My multimeter is telling me 7.8VAC which is perfect for what I was intending to use it for. I don't know the current output...but I suppose my multimeter could do that somehow...

I'm no longer afraid of AC.

Thanks to all.

 

Now all you have to do is figure out this double posting thing

 

Stereo?

John

 

How...what...how did that get here...I should just go to bed.

 

Stereo?

John

Haha. Very funny.

 

Measure resistance with multimeter low resistance is Primary.

 

Measure resistance with multimeter low resistance is Primary.

Ritesh: That is neither a correct nor safe assumption. Where did you get that idea?

John

 

But if using two identical transformers secondaries wired in series to get a higher out- put voltage, they must be wired 'in phase'. Most transformers have a "dot" printed by one out-put lead, this lets you wire them in the correct phasing. From our own reference book,here; http://www.allaboutcircuits.com/vol_2/chpt_9/4.html

 

Are you trying to figure which is the primary vs. secondary?
There is no polarity in a transformer, not hot, nor ground.
A transformer is an AC device, and it isolates the two sides, and is not connected to the core.

Nah...Transformers may indeed have "polarity". There are some rules that apply to winding interconnections - if you break them, you may break your transformer as well.
I have two links for more about this
http://sound.westhost.com/xfmr2.htm#s8
http://solderman.dapj.com/2005/09/transformers-series-and-parallel.html

 

Nice links. (I wish I knew how to do links!) but neither of them picture a transformer like the one in the photograph (posts #12 and #14).

 

Start another topic on links, they are easy.

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Back on topic, there is an AC polarity associated with transformers, 0° phase shift and 180° phase shift. Many oscillator designs use this (such as Armstrong oscillators).

The thing I've always loved about transformers is, like a motor (and for the same reasons) they only pull power when it is delivered. No load on the secondary, very little load on the primary. One of Dr. Tesla's better ideas.

 

Ritesh: That is neither a correct nor safe assumption. Where did you get that idea?

John

Simple, for step down transformer primary resistance is more compared to secondary.

 

Simple, for step down transformer primary resistance is more compared to secondary.

Still, bad assumption. You don't know if a transformer is a step down or not, without markings who can tell? Transformers are also reversible, which is handy for an inverter. I love it when the manufacturer puts the specs on the case of the transformer. This used to be the standard.

 

It depend on rating of it, as if we connect step down transformer reverse to high supply line (i.e. 220V) i seen it blast with good sound.

 

As a thumb rule then it comes to 50/60 Hz power transformers. The wire thickness used in the windings will most often point you in the correct direction. For a transdormer meant to work as step down transformer. The sencondary will in most cases carry more current and have thicker windings. But if you are unsure do not connect the transformer to the mains at all. Not all transformer are power transformers meant to be used for the hobbyist in linear power supplys

 

It depend on rating of it, as if we connect step down transformer reverse to high supply line (i.e. 220V) i seen it blast with good sound.

That is just plain dumb to do. Why did YOU do it?

John