[sdiy] thermal coupling question

Wed Jan 22 00:22:17 CET 2003

Hello all...

I like a big gob of epoxy... that covers the expo and tranny
(similar to the old Aries modules)... its hell to repair and
if the tranny dies you lose the expo...

but it shields very well against drafts, etc.

I pot the tranny and expo in little plastic caps (like those made
by Caplugs)... or the safety caps from pump type hair spray (for those
diy-ers who either still have wives... or hair....) ;^P

H^) harry

>Hi Micheal and all,
>If I Recall Correctly, somebody on the list constructed a neat little package using an SMT transistor pair and tempco resitor mounted on an 8 pin DIP header.
>Thermal tracking is best if the expo and tempco are in good thermal contact with one another. You may get away with simply placing the expo and tempco near one another if the inside of your enclosure is free of drafts or abrupt temperature changes.
>On the other hand, expo transistors do tend to generate a very small amount of heat of their own, so it is best to thermally couple them to the tempco.
>Yeah - the expo-grease-tempco sandwich approach is ugly, but it does work well.
>Oren
>-------Original Message-------
>From: Michael Schulze 
>Sent: 01/21/03 12:05 PM
>To: synth-diy at dropmix.xs4all.nl
>Subject: [sdiy] thermal coupling question
>> 
>> I have a question for the group on thermal coupling.
>I am building a quad vco based on Jorgen Bergfor's design.  The expo
>converter (in my circuit) contains of a tempco resistor and a MAT-02
>transistor pair.  The MAT-02 is in a can enclosure - you know - like a
>TO-72
>but with 6 leads.  The pcb has a space for an 8 pin dip on which Jorgen
>assembled smt devices.  Not being an smt whiz I am just assembling my two
>huge crude components on an 8 pin dip header.
>So my question is how to achieve the best thermal contact.  Do the two
>components need to be physically touching or can they just be next to each
>other with a dollop of some magical heat conducting compound binding them
>(...in the darkness...).  I'd hope to come up with something more elegant
>than heat sink grease...
>Thanks in advance
>> 