Problem with testing WB (heater circuit)

[Brian Renegar]

>Looks like C3 is OK; it would probably get hot if bad.  Check
>putting 14 volts on the supply; 13.5V is marginal.
>
>Bruce

Well, I figured it out.  Dumb old me had the LED in 
backwards.  D'oh!  Works better the correct way.  :)  Currently I have one 
resistor (15 Ohm I think is what Steve added to the kits) added to R4.  LED 
comes on in 45-50 seconds.  Current draw through the heater is 1.402A, 
which reduces to approx. 1.28A once the sensor is hot.  Vout is between 
3.96 and 3.97 V.  Is that close enough??  I know it's supposed to be 4.00V, 
but due to variation in components, am I ok?  One other question 
though...  After the LED turns on, it appears to still take 10-15 seconds 
for the Vout to stabilize.  It ramps up and then tapers off at 3.97V.  Is 
that normal?  Is the sensor still heating up, or is something else going on?

Thanks for the help,
Brian

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