@monte said in INA219 current sensor with PWM Ruideng 3W LED driver:

N-channel mosfet

Thank you monte,
I tried connecting the GND directly to IN- but, although the Load voltage on the INA219 is pretty stable at 9.4 V , the current is still jumping from -1.4 up to 160mA.

I have set up an INA219 to measure current draw and voltage on 3 X1W LEDs connected in parallel. I set up exactly as the INA219 instructions and it seems to be working fine. I also added a PWM dimmer to the power supply and using a pot I can alter the brightness from 0 to full brightness. Now the problems occur when I try to use the INA219 to measure the current between the LEDs and the PWM Ruideng dimmer. If I don't run a ground lead from the power supply back to my Arduino Nano, the LEDs dim like they should but the INA219 readings are erratic and only occasionally show readings that I believe are correct. So I run a ground lead from the negative of the power supply - as it leaves the PWM Ruideng module -back to my Arduino. That makes the readings from the INA219 look good and are very stable, however, I lose all the dimming of my PWM Ruideng module and the pot doesn't make any difference and power to the LEDs jumps to full.