How can i design constant current source (1mA) for a resistance based temperature sensor. Sensor resistance is 2Komh. (LM317)
Because i do not understand this topic fully im not sure about correct description of my problem, I hope you can help me out.
Basically... I need to to integrate a thermistor to a PIC MCU. 1mA cont source current seems good because i can get 2 V as voltage drop, out of 2Kohm resistor in series .
This source provides a constant current supply to a circuit load. Note that the transistor current source is inside the feedback loop. Here, R1 and R3 make a voltage divider to set Vref, but Vref could be set by some other voltage signal, instead. The current is determined by the formula: