Tool/software:
I am having an interesting issue with the LM358P dual op amp. In our circuit this op amp is used after a LOC111 opto-isolator to amplify a DC motor signal. We then set our Zero and Span pots to a specific low (park) speed and a higher operational speed. When we put the DMM across the DC output and the isolated ground it bogs down the motor and causes it to oscillate, this happens if the lead is connected to the DMM or if it is floating (almost acting like an antenna for noise). If we do this same process on an older LM358P from say 2018 or so, the problem is not present in the exact same circuit with the same components. Any ideas as to what is happening here?
