> More to the point: adding something with leads to something with 
> leads means
> adding a radiator. To actually measure the temperature of a point 
> without
> cooling or heating it one sets up a gradient meter. That's like a 
> Wheatstone
> bridge for heat. It works like so:
>
>     insulation
>       ======
>  H/C--T1--T2--Target
>       ======
>     insulation
>

That's essentially the same as what I proposed, but I used one sensor 
to do both jobs and you had to move the sensor to the heater and back. 
Your bridge system is eminently more practical.




        Russell 

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