[sdiy] Was PTC/NTC intelectuall level of SDIY!

[Ian Fritz]

At 07:16 PM 3/20/2008, Bruce Duncan wrote:

>On the data sheet the figures for hie look similar to a thru-hole 2N3904 
>at 1-10K. I used to use CA3086 and have noticed that they require less 
>comp. than the 3086 in the same application.
>I went with them because the Vbe matching is stated to be typically better 
>than 1mV.

Very interesting.  I'll have to try them vs the CA3083 that I usually 
employ.  I know from my own measurements that the Re is somewhat larger in 
the thru-hole 2N3904 than in the 3083.  Thanks for the hint!

>I haven't noticed this phenomena but I do use a fair size glob of 5 min. 
>epoxy which may be sinking any minor self heating.

Good point.  The one I have on my new filter prototype is soldered to a 
surfboard, and I assumed that would be good enough for heat sinking.  I'll 
blob it up with epoxy tomorrow and see if there is any difference.

Ian