[sdiy] what makes a transformer vibrate?

[The Peasant]

Quoting Nils Pipenbrinck <np at inverse-entertainment.de>:

> Is this a problem, and how to get rid of it?
> 
> I have a old Nordmende transistor radio from the 60th in my kitchen. 
> Don't use it much, but yesterday evening I noticed how loud the little 
> power transformer vibrates. It's the original external mains adapter, 
> and I don't want to replace it. (it's just a 220V to 12V transformer, a 
> fuse and 4 rectifier diodes, but the housing and inner life are still 
> original and look very funky).

Some causes of transformer hum are undersized core, loose core pieces, and DC 
or noise on the power line. It may just be a low quality transformer. Torroidal 
type transformers are much more sensitive to DC on the power line than other 
types.

It should not be a problem other than the annoyance from the vibrations, you 
could cure it by replacing the transformer or using a DC filter on the mains.

Take care,
Doug
______________________
The Electronic Peasant

www.electronicpeasant.com