replacing a plug-in transformer

[lozina]

I had a power surge earlier this year which fried some transformers in my basement. Most of them were pretty easy to find replacements for except there's this one for my exercise bike computer... it says it's got 120v 60hz 15W input and outputs 500mA at 12v.

I could not find the same exact transformer doing a search for it's product number, but I could find many 12V 500mA transformers. The problem is, they are all listed as 11W. I cant find any that are 15W. But this got me thinking... isn't the formula W = VA ? So how is possible that the same 12V 500mA transformers have varying Wattage? I don't get it...

Should I try using one of the 11 W transformers to replace it with?

 

[Colt45]

It can be >500mA, not really important. Just make sure that the polarity is correct and that it's 12v and >=500mA

 

[jagec]

The output's all the matters...

 

[Leros]

The wattage doesn't matter. All you care about is voltage and current.

The wattage difference probably have something to do with the efficiency of the transformer.

 

[So]

Originally posted by: Leros
The wattage doesn't matter. All you care about is voltage and current.

The wattage difference probably have something to do with the efficiency of the transformer.

Yup. Just make sure you get the right polarity (center positive or center ground).

 

[Jeff7]

1) Amperage of the replacement should be higher than or equal to that of the old one.
2) Polarity is important.
3) If it's a DC transformer, make sure you don't get one with AC output. Sounds pretty basic, but some people will not pay attention to this.

 

[So]

Originally posted by: Jeff7
1) Amperage of the replacement should be higher than or equal to that of the old one.
2) Polarity is important.
3) If it's a DC transformer, make sure you don't get one with AC output. Sounds pretty basic, but some people will not pay attention to this.

3) Good point.

 

[Demon-Xanth]

Wattage wise, if it's output is 12V@500mA, it's output is 6W.