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Formula for measuring temperature from LM35dz

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handsprince

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volt1 = (temp1*5)/1023; //Arithmetic calculation
humidity = 20*volt1;

above is a c programming to measure a temperature from LM35DZ, but i'm not understand with the formula above, can anyone explain for me?
thanks a lot
 

Re: LM35dz

Hi,
The first part of the statement is understandable as:
You are using a reference of 5V, for which ADC produces a full scale count of 1023. So if your count = temp1, equivalent voltage volt1=( 5÷1023)*temp1.
=( 5÷1023)*temp1*1000mv
Assuming you are using it for up to 100°C and you used a gain of 5 to get 5V at 100°C, then by dividing the above by 5, you get
Actual Sensor voltage =( 5÷1023)*temp1*1000mv ÷ 5
= ( 5÷1023)*temp1*200mv
Since the sensor outputs 10mV/°C,
Temp = ( 5÷1023)*temp1*200mv ÷ 10mV/°C = ( 5÷1023)*temp1*20°C.
But why Humidity?, I do not know.
Regards,
Laktronics
 
Re: LM35dz

thanks laktronics, actually i'm using a sensor to measure humidity and temperature.. :) really thanks for ur help
 

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