LM 35 noise problems

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manu4fun

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Hi guys need some help in designing a circuit to removing the noise from lm35 output.There is a large variation in the temperature being shown(from 33 to 44C) in the 16X2 LCD .I am using adc0804 & at89s52 for temperature controlled fan project. From what i read here the variation is caused by the noise in the circuit & i need to use a RC circuit for removing the noise but i dont know what values are to be used?.
 

Generally, a simple low pass filter based on moving average shift is quite enough for damp little deviations. However, the magnitude of dispersion you´re facing is very high. Post your circuit for a better analysis.




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At first it is showing the correct temp ie about 31C then it jumps to 40-44C & then remains constant in that range .I have attached the ckt here.
 

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Once such behavior is not happening on real world but just at a simulated environment, we could not properly denominate this as a noise. Probably occurs due to the time required to stabilize the final state.



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Although they may not apply in your case, the datasheet has some suggestions on what to do with different loads.
 

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