The ESR of an electrolytic capacitor decreases slightly when the capacitance increases. However, it is fundamentally difficult to control the ripples by increasing the capacitance. This is because the time constant increases together with the increase in capacitance. The response speed of a transient phenomenon such as the charging and discharging process of a capacitor can be expressed as the time constant index called (T). In an RC circuit consisting of the resistance (R) and the capacitor (C), the time constant becomes T=RC (R is in units of ohms [Ω], the capacitance C is in units of farads [F]). The time required for charging and discharging of the capacitor is short when the time constant is small and becomes longer as the time constant increases. The time constant becomes extremely large when using an electrolytic capacitor with an excessively large capacitance.