Electrolytic capacitors can fail in one of two main ways, open or short. Failures can be the result of electrical, mechanical, or environmental overstress, "wear-out" due to dielectric degradation during operation, or manufacturing defects. Polymer capacitors are supposed to fail in this manner and it is much preferable than failing shorted as discussed below. Capacitors can tend to dry out (though usually it's electrolytic ones that do this). The following diagram explains how to decode the common "six dot" scheme used in many micas. This white paper discusses the reasons capacitors fail, the dispersion in time An electrolytic that fails short will blow the power supply fuse if the equipment has one. The thermally induced failure mechanism in wet electrolytic capacitors is triggered by electrolyte evaporation at high temperature. In an electrolytic that has failed open, the capacitance is reduced to a small value because the electrolyte has dried out. Due to their very thin dielectric oxide … …and Marc addresses this in the video. A solid, liquid, or gel electrolyte covers the surface of this oxide layer, serving as the cathode or negative plate of the capacitor. Electrolytic capacitors do not usually fail shorted, and there are fuses to protect the transformer in this device. The anode always needs to be connected to a higher voltage. In electrolytic capacitors, the dielectric can crack in both low- and high-energy surges. When the electrolyte touches the aluminum through the crack in the dielectric, a reaction occurs that rebuilds the dielectric. Replacing capacitors periodically is the only way to insure a very high MTBF for capacitors. If you fit a different value then it will effect the crossover frequency so not recommended. For other color coding schemes, try this Google search. Failure depends upon the capacitor type and enviroment (primarily voltage, heat … For instance, if one capacitor in a bank of caps has an internal flaw, then the rest of the caps in the bank can all discharge into the fault. In addition to these failures, capacitors may fail due to capacitance drift, instability with temperature, high dissipation factor or low insulation resistance. However they can also fail … If you wire it up the other way around with the cathode getting a higher voltage, then prepare for an exploding cap! Capacitors, especially large electrolytic capcitors in power supplies, do tend to fail over time, but it can take a very long time... Like, 10+ years (and in some cases decades longer). Mica capacitors rarely fail, but occasionally you'll find a bad one. Capacitor failure models do exist and will generate a failure time for a specific failure rate but the number contains a large variance and has a low confidence level. Electrolytic capacitors can fail due to many reasons such as high temperature during soldering, internal power dissipation due to ripple, etc, high ambient temperature, reverse voltage, voltage transients, etc. On these electrolytic capacitors, there’s a positive pin, called the anode, and a negative pin called the cathode. Electrolytic capacitors also have a self-healing ability, although to a lesser extent than film capacitors. Electrolytic capacitors, housed in large metal or cardboard tubes, usually have their values printed on the case. A capacitor can fail open so that it is disturbing the flow of electricity in the circuit and then the circuit is no longer working at all. All that energy flowing into a defective (shorted) cap will very likely cause explosive failure, by vaporizing the liquid dielectric in an electrolytic capacitor. An electrolytic capacitor is a polarized capacitor whose anode or positive plate is made of a metal that forms an insulating oxide layer through anodization.This oxide layer acts as the dielectric of the capacitor. fail.