12V Electronic Tranny

How about tracing the circuit and posting a nice ASCII schematic, with component values, for us to sink our teeth into? Maybe you could unsolder the transformer and characterize it as well? :-)

--
 Thanks,
    - Win

Iron powder devices can have poor performance as they age, under heat, and can catastrophically destruct. Maybe it's due to that.

I'd be interested to see if it still only warms by 10C at 50C ambient.

Hello Ian,

They also have a rather large tolerance.

Regards, Joerg

"Winfield Hill"

** Win's trolling is getting more and more desperate.

....... Phil

"Ian Stirling"

** Dunno where you saw any mention of "iron powder".

The wound parts all have ferrite cores.

........ Phil

unless the iron powder core has gone rusty, its pretty hard to tell it from ferrite. especially if the cores are coated.

Cheers Terry

** The transformer cores are uncoated ferrite.

The temp rise is but a few degrees.

Your shift key still faulty ??

........ Phil

The important temperature rise is that of the ferrite cores inside the winding. Some ferrite materials have Curie points down to 100C, so your part may need to run a lot colder than you might expect.

--
Bill Sloman, Nijmegen

** The output transformer is made with two ferrite E cores - so most of it is in free air.

As stated - the temp rise with 100VA load is not more than 10 degrees C.

BTW

The two switching devices are actually BJTs.

ST 13007 DFP.

........ Phil

The temperature rise at the surface of the transformer maybe 10C under the conditions of your test. The heat is being dissipated inside the coil and inside the ferrite. For the heat to flow to the surface, there has to be a temperature gradient in the ferrite and in the coil. Copper is a pretty good thermal conductor, so you don't get much of a thermal gradient in the coil. The ferrite is a better insulator - nowhere near as good as air, but lots better than copper.

You'd need to drill an angled hole into the ferrite under the coil to get closer to the temperature rise where it matters.

You also need to worry about the degradation in the performace of the ferrite with increasing temperature. It completely stops being ferromagnetic at the Curie point, but it isn't up to much when it gets close to that sort of temperature.

--
Bill Sloman, Nijmegen

** What a load of **f****ng** gobbledegook !!!!!!!

The core is TINY !!

There is SFA temp gradient .

** Is this ranting f****it on drugs ?

Or has he forgotten to take them ????

** Sure - at 150 C maybe.

Not 50C.

Piss of slow man.

......... Phil

What's your problem, man?

Jeezis, Allison, can't you keep a civil tongue in your head even when your asking for our help?

Screw you.

Rich

If I haven't dumbed down the message enough already, you need to post your questions on sci.electronics.basics.

What is tiny in millimetres (or inches - I happen to understand both).

Not a recognised egineering unit. You seem to want to think that it is negligible, but until you've done the minimal amount of work needed to work out what it might b, you are just an optimisitc idiot. Had you asked nicely, I might have taken the time to do some of the work for you.

Sure - a beta-blocker, and ACE-inhibitor, a statin and a trivial dose of some diuretic, which my little brother suspects of synergy with the ACE-inhibitor.

Obviously not, or my blood pressure would have gone through the roof while reading this twaddle.

Depends on the ferrite. Some are good 450C, some fall over at 100C.

How would you know?

Your abuse is at the same infantile level as your electronics. Go and read some Richard Steven Waltz, and see if you can raise your game to merely despicable.

--
Bill Sloman, Nijmegen

"Mochuelo"

** Too many deadheads like you on usenet.

........ Phil

"Rich Grise"

(snip childish & mindless abuse)

** The day this Grise cretin adds other than misinformation to NG will be a cold one in hell.

........ Phil

** What pathetic, posturing old fool you are.

Piss off.

** The core is 25 mm square.

The whole tranny is 25 x 25 x 22 mms.

** Piss off - you posturing old FOOL. ** Shame there is no cure for autism or narcissism.

** When you get something right - I will let YOU know.

Meanwhile - piss off.

......... Phil

You're most likely infringing upon safety margins of the components. What's your problem that you couldn't buy a 150W unit? The circuit your dealing with is a MOSFET version of this, a self-oscillating half bridge:

Cretin is way too good a word for that ignorant sociopathic fag...