
#1
Sep2107, 11:10 PM

P: 1

Hi,
I'm having some questions about the way I could achieve to maintain the power in a resistor constant. My problem, is that the resistor is quite small (less than 100ohm at room temperature). When running, the resistor, a heating resistor, heats up to 300celcius. So, the resistor change in function of the temperature. So, to maintain that temperature, I want to keep the power of the resistor constant. I have some ideas to achieve this, but I have some misunderdstanding so I miss something. Here is my mind : RL = Resistor Load (heating resistor) 1. find IRL : adding an Rsense of about 1ohm serially with the RL. 1A = 1V on the ouput of the opamp 2. multiply the IRL with the VRL. Obtain Power 1W = 1V. 3. find delta Power (substract Power_Setpoint from Power (step2)) 4. ?????? > using (step 3) change the current or the voltage applied to the Rsense to obtain the perfect power. I though to use a microcontroller to control this, but I was wondering some precision issues... So, do somebody have some suggestions ? Do some circuit do this ? Am I doing this right ? Thank you for your help 



#2
Sep2207, 04:34 PM

P: 167




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