/diy/ - Do It Yourself

Does anyone have any advice on how to find out which lead is connected to the outer foil on film capacitors? I have tried using my oscilloscope, where I set the voltage/div setting to 5mV on the channel that I'm using for testing, and played around with various time base settings, but there is no discernable difference between the two different ways that I hook up the capacitor. Alternatively, I have tried using a guitar amplifier to identify which lead is which, but once again there is no discernable difference. I have done the test in a room which has LED overhead lighting while having my finger on the outside of the capacitor to induce some noise in it. What am I doing wrong? I have watched some videos of people using these two techniques to identify which lead is which, and they have a night and day difference between the two orientations. I have also tried putting the capacitor near a dimmable halogen desk lamp that has audible 60hz noise when set to a dimmer brightness to no avail. Are there any other techniques that I could try?

i want to build an ereader with a rasp pi and an eink display (i had this from waveshare in mind https://www.waveshare.com/product/displays/e-paper/epaper-1/7.8inch-e-paper-hat.htm))
is there anyway i can implement touch functionality to this display? i searched for touch digitizers but i found nothing usefull
im a beginner and also a fucking retard, if you have any useful resources i would appreciate them