-5V to 5V range with Arduino PWM, an op amp and a symmetric power supply

[jim-p]

I thought we solved the current measuring issue in your other topic

Current–voltage characteristic of a pin

Hi everybody, I'm trying to plot the current-voltage characteristic of a single pin of a micro-sd card. I came up with a test circuit with a diode to know where I'm going. I'm generating a voltage between 0 and 3.3V with the PWM mode of my Arduino Due. I also filter the signal with an RC filter (R=15k and C=1uF) and I added a buffer (with an operational amplifier LM258 that I power with the 5V output of the arduino). The output of the amplifier is connected to both the A0 input of the arduino …