Re: TI-H: Digital temperature sensor (LM75CIM-5)


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Re: TI-H: Digital temperature sensor (LM75CIM-5)



> Ok, I got the LM75CIM-5 chip and buildt a little circuit board for it but
> when I run the sensor.85s in usgard, I get readings that are not correct.
> It says 0 C and 32 F.  I used silicon switching diodes and a capacitor I
> found in some old kit.  I think it mught be the capacitor, what kind/size
> should I use. The one I have says:  104M.  (capacitors are the little round
> kind of flat yellow/brown/orange guy's right?)
> Thanks, 
> Corey
> This message brought to you by Corey Runge, His ISP, and the letter 

I'm not sure exactly what the problem is, but try using larger size 
capacitor.  The small yellow/orange/brown ones are not ones of very 
high capacitance.  I would recommend trying something more like a 
small electrolytic capacitor which are the black or blue ones that 
look like small "cans".  The value I used was a 10 uF (microfarad) 
capacitor, but I have also tried values such as 2.2 uF and 100 uF, 
both of which worked flawlessly.

As a technical note, the capacitor is used to provide power to the IC 
from the link port terminals.  The problem with the terminals is that 
they are not always turned on to power the IC.  So, the capacitor is 
used to filter this pulsating voltage and keep it at a level high 
enough between pulses to power the IC.  

Ed Plese
http://www.geocities.com/siliconvalley/bay/2267


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