[sdiy] Switching power supply transformers

[Roy J. Tellason]

On Thursday 13 January 2005 04:41 pm, Harry Bissell Jr wrote:
> Another note is to consider the symptoms of an
> under-loaded supply.

Noted,  a bit earlier on in this thread.

> The voltage may become unstable (which could mean doom
> for the 5V logic)...

Yes.  Crowbars are also nice things to have,  at times.

> The supply may operate in what is known as "burst mode"
> the supply will run at the normal switching frequency
> until the 5V level is reached, then shut offf while the
> DC voltage bleeds down, and starting the cycle over.

Which is why I said "measuring the voltage" in there,  in the part about 
testing things out...

> Most switchers rub well above the audio frequency... but if they go into 
> burst mode they will probably cause audible sound, as well as interference 
> with the rest of the synth circuit as a whole.
>
> Even if the burst mode does not kill you, you may wish
> you were dead...   :^P

I've heard that,  and even with my hearing damage it's *awful*!