I am trying to measure the current using sense resistor method.
Low Side Current Sensing method:
- I am using shunt resistor in the low side, there will be a voltage drop across the resistor.
- Since the voltage drop is very small, using op-amp we can amplify to the required voltage level for microcontroller's ADC input.
The ratings are I = 30 & R = 0.001 (2 watts)
Voltage drop across the resistor,
Vrsense = IR = 30 * 0.001 = 0.03 volt
Power dissipation in resistor,
P = I * I * R = 30 * 30 * 0.001 = 0.9 Watts
Vout = Vrsense * (1+ Rf / R1) = 0.03 * (48) = 1.44
My doubt is LM358 has a maximum power supply of 36 volts, but I am using 50 to 60 volt. I thought that the input channel will allow zero current, so by giving such a supply will not be a problem. Since I am new to op-amp correct me, friends, if I am wrong. Or I have to use some other op-amp.