another type of Capacitor
polarized large level of farad typically 1uF to 40mF can have high working voltage up to 350V High ripple current capability High leakage & poor tolerance Poor performance at high frequencies they are terrible but can have very huge farads overheading or overleading may cause to explode they dry out in time, increases series resistance higher temp, shorter life if you mount this near heatsink, it will make it fucked up. need to be in cool place not near to the heat elements. But not too cool, then it makes it high esr you need to use quality ones for reliable design= use a couple of that in parallel, find good low esr for smps reverse voltage is about 1.5V, take care! cheaper high esr, low lifetime