What’s Wrong With This RC Circuit Experiment?

Photo: Rhett Allain. RC Circuit Setup

It’s pretty much a classic physics experiment. Take a resistor and a capacitor and connect it to a power supply. As the capacitor gains charge, the total current decreases. Eventually, the capacitor will get mostly charged (technically it doesn’t get to 100 percent).

But if you choose appropriate values of R (the resistance) and C (the capacitance), this thing will charge slowly enough…