The internal resistance of supercapacitors

In this paper we study the transient behaviour of RC circuits with supercapacitors, varying R between 1 and 100 Ω. We demonstrate that supercapacitors behave as ideal capacitors in series with an internal resistance (r ∼ 8 Ω for C = 0.2 F, 5.5 V). This result is important to optimize the demonstration of RC circuits using a supercapacitor in series with a light bulb, because the r value is comparable with the effective resistance of the bulb. This means that the bulb brightness is significantly decreased by r.