Working with my Fez panda, I recently found a behavior that was unexpected for me. I had thought that when PWM is being used, the voltage will be stable, and it is the duty cycle that changes. Thus if I measure the voltage with a DMM, it will see the peak voltage. Instead what I have found is that the DMM will see a different voltage when a port is switched from 30% duty cycle to 100% duty cycle.
is this a side effect of PWM and as such a DMM just won’t be accurate? Or is there really a voltage changing going on?
The reason why I’m so curious is that I used the total output voltage to calculate proper resistor sizes, and if I find it is moving around, that will influence those calculations.