[sdiy] Chip Tempcos, Solder paste and toaster ovens

[Ingo Debus]

Am Donnerstag, 31.03.05 um 20:17 Uhr schrieb Tony Clark:

>
>> In a nutshell, I may have to solder an expensive NPN pair in a TO-71 
>> can to
>> a board using solder paste so that I can get it down close enough to 
>> the
>> board surface soo it rests upon a chip resistor. Basocally - REAL low 
>> to the
>> board. Problem is, when the tranny is down that far I can't get to 
>> the leads
>> to solder them (non plated through holes).
>
>   Put it upside-down on the chip?  That way the leads are sticking up 
> and
> then you can wire them however you'd like.


I've often read that at least for transistor in plastic cases most of 
the heat transfer from/to the chip is via the leads and not the case. I 
don't know if this is true for metal can trannies too.
So it's probably a good idea to keep the leads short and their pads on 
the PCB close to the tempco.

Ingo