Read a voltage from a two terminal of resistor

[baby_1]

Hello
Here is my circuit that the ground are share with my MCU circuit (i want to find the rtd resistance)

if i want to find the voltage accross the RTD sensor( that a temp sensor that changes his resistor) i get the voltage from pin 6 and minus 2.5 volt from it and them divided it by his current(2.5/330) to find the resistor.

this way has a problem , you should know the exact current and voltage on the pin 2,
there is no any way that can find the voltage across from RTD with MCU better than my way?

Thanks

 

[gonespa]

Hello
Here is my circuit that the ground are share with my MCU circuit (i want to find the rtd resistance)

if i want to find the voltage accross the RTD sensor( that a temp sensor that changes his resistor) i get the voltage from pin 6 and minus 2.5 volt from it and them divided it by his current(2.5/330) to find the resistor.

this way has a problem , you should know the exact current and voltage on the pin 2,
there is no any way that can find the voltage across from RTD with MCU better than my way?

Thanks

Not sure what you do want to achive. Measure the temperature with and RTD sensor an feed it to an Analog to Digital port of you MCU?

 

[FvM]

The circuit can work with a standard OP, presumed you add power supply. It won't work with AD622 that's not designed for overall feedback.

this way has a problem , you should know the exact current and voltage on the pin 2

Neither a problem. OP input current can be neglected and pin 2 voltage assumed to be equal to pin 3 voltage.