-=> Roy J. Tellason said to Greg Mayman
 -=> about "POWER SUPPLY" on 12-25-03  04:06.....

 RJT> What got me about that was that there were times when I worked on that
 RJT> equipment and saw some signs of heating in those resistors.  You
 RJT> wouldn't think they would,  much.

No. Either the driver circuit is off and the resistor carries no
current, or it turns on and triggers the Triac, and there is no
voltage across the resistor.

The only time the resistor should be disipating power is during
that very brief time after the trigger circuit is on and before
the triac turns on.

Well, that's the theory...

 RJT> So it'd be a very short pulse in any case.

That's the theory... of course it may be that some devices don't
believe in the same theories that we subscribe to 
 
 GM> Yeah, too much of the stuff is large scale integration that you
 GM> can't do a darn thing with except change the chip :-(((((

 RJT> Unless it's surface mount,  at which point you change the board...

Yeah. Damn frustrating, isn't it...

 RJT> And yet there seem to be hobbyists who are embracing that sort of
 RJT> thing.  I'm not sure why that should be.  It may be that some parts are
 RJT> only available that way (though I don't see the need to use those
 RJT> parts),  and the compactness and light weight can't be serious
 RJT> considerations in the stuff I was looking at -- other factors overrode
 RJT> this. 

Some parts are only available that way. And you could possibly
replace them by a whole swag of conventional devices, but if you
want it all in one chip, you take what you can get.

I think a lot of hobbyists today are more interested in building
the projects than in keeping them working for some foreseeable
lifetime.

If something dies later down the track, they'll start to worry
about it at that stage...

 RJT> The single major factor I can see that makes surface mount an
 RJT> advantage in manufacturing is that you can put stuff on both sides of a
 RJT> board,  and that board layout gets a whole lot easier and more direct. 
 RJT> More so in multilayer contstruction,  as in MBs.  About the only
 RJT> advantage I can see for a hobbyist is not having to drill quite so many
 RJT> holes,  but assembly isn't something I'd consider easier!

Surface mount is a lot smaller, even if you still only use one
side of the board.

 RJT> Personally I don't think I'm gonna bother with it until such time as
 RJT> regular through-hole components just aren't available any more,  and I
 RJT> don't see that as happening any time soon.  Particularly not with the
 RJT> pile of stuff I've scrapped out over the years.  :-)

The problem with surface mount is that I have to use magnifying
specs to see the things. It's bad enough just trying to read the
part numbers with conventional components.

From Greg Mayman, in beautiful Adelaide, South Australia
   "Queen City of The South"    34:55 S  138:36 E

... Time is Natures way of stopping everything happening at once
___ Blue Wave/386 v2.30

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