Just wound a 1 to 1 transformer by hand in 1 minute.

That would have been my first choice.

The gadget with the glued-down transformers bought our building.

ftp://jjlarkin.lmi.net/Painted.JPG

And got us an award.

ftp://jjlarkin.lmi.net/NIF3.jpg

So your whining makes no sense.

John

We're lucky here in the USA. Lots of manufacturers and distributors stock things like pot cores, and I can usually get free samples, or a kit, in a day or two. I can fill out a form for TI samples in the afternoon, and have the parts on my desk before I stagger in the next morning.

Yes,

"Isolated" up to the breakdown voltage of the ssr's, 400 volts maybe.

John

Yep, that's the stuff.

Cheers, James

These put 5 volts into 50 ohm loads, so we use small cores and 3 turns. High-voltage versions are bigger.

ftp://jjlarkin.lmi.net/Xfmrs.JPG

John

Aw shucks. I was kind hoping you were getting interested in bigger power. Can you competitively make 12.5 kV, 200 A, 3 phase subcycle transfer switches?

Heavy iron tends to be less profitable, and less interesting, than putting tiny parts on boards. We prefer to build things that won't break your toe if you drop them.

John

That is some nasty looking soldering...

Never had one joint fail. The VME module that this plugs into has something like 6x better field reliability than Bellcore calculations... 500K hours or so, based on over 1000 unit-years of history so far.

You seem to dislike everything and everybody. That sort of rage will kill you before your time.

John

I was an In-Process Inspector at one time. I can look at a ten thousand node assembly (older, not BGA stuff) and literally spot a single badly formed solder joint from a single 30 second (or less) glance. I was well loved as such. Those are pretty grainy lookin. Even the SMD devices appear as hand soldered.

When I soldered back then, my SMD work looked like it came off a pick and place line. Those terminations are "blobby". Not a lot, but there are plenty of terminations that are not 'concave' in appearance.

Your brain is bent. It was an honest, and valid observation. There was, nor is there any rage. I do dislike they way you take your criticisms.

Of course they look grainy. The average pad in that image is around

The "well loved" bit is a little hard to believe.

John

Not if you're the factory "queen" ;-)

...Jim Thompson

On a sunny day (Wed, 07 Jan 2009 10:19:28 -0800) it happened John Larkin wrote in :

I looked and my fist impression was also 'not a very good joint', but then looked closer and it seems alright with me. I am one who checks every hand soldered connection *by me* with a magnifying glass.... Remember something about milspec.. You would not believe the number of joints that look good but are not. When I was in the TV repair business bad solder joints was a big percentage of the faults, especially in the old tube sets, all due to thermal stress. Hot coils qualify too for thermal stress.

stress.

We have some great assemblers and a couple of superb inspectors, not to mention a lot of expensive optics. Our first concern is electrical integrity and reliability, and we only consider cosmetics if a joint is truly repulsive. We have had an insignificant number of field failures that can be blamed on soldering.

Interestingly, after placing and soldering some hundreds of BGA packages in-house, with ballpark 500 pins per package, our all-time BGA soldering failure rate is precisely zero.

John

Scant danger of that, in most cases even very strong humans cannot lift them. (Over 500 LBS)

Here's our pick-and-place machine for a power transformer...

ftp://jjlarkin.lmi.net/PP5.JPG

The finished amplifier weighs more than one of our employees.

John