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how to generate a fixed current to RTD sensor

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gameelgamal

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the RTD is a thermal resistance, Its value changes with the temprture

So, how to generate a fixed current to RTD sensor???
 

HI DEAR,

WOULD YOU LIKE TO TELL THAT WHERE YOU ARE GOING TO USE IT I MEAN IN WHICH APPLICATION
 

gameelgamal,
One way is to use a high voltage supply in series with a resistor with a value that is much greater than the nominal resistance of the RTD. The higher the ratio of seris resistance ot the RTD resistance is, the closer the circuit will approximate a constant current source.
.
A more elegant solution is to use the "Howland" constant current source. See, for example:
.
h**p://ieeexplore.ieee.org/iel5/9009/28599/01279429.pdf
.
Google on "Howland circuit". You'll get lots of hits.
Regards,
Kral
 
vicky said:
HI DEAR,

WOULD YOU LIKE TO TELL THAT WHERE YOU ARE GOING TO USE IT I MEAN IN WHICH APPLICATION
Click to expand...

Right now,There is not a certain application
you can say I want to measure the temp. and display it on LCD

Added after 3 minutes:

Kral said:
gameelgamal,
One way is to use a high voltage supply in series with a resistor with a value that is much greater than the nominal resistance of the RTD. The higher the ratio of seris resistance ot the RTD resistance is, the closer the circuit will approximate a constant current source.
.
A more elegant solution is to use the "Howland" constant current source. See, for example:
.
h**p://ieeexplore.ieee.org/iel5/9009/28599/01279429.pdf
.
Google on "Howland circuit". You'll get lots of hits.
Regards,
Kral
Click to expand...

the link doesn't work with me, I think it is for IEEE members and I'm not

could you explain briefly about what do you mean by HOWLAND
 

Did you Google "Howland current source"?
 

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