Power Supply Filter Capacitor Failure

The lc filter shown in fig.

Power supply filter capacitor failure.

This large current may damage the diode and at the same time it causes greater heating of the power transformer resulting in decreased efficiency. The result of extended exposure to higher than rated voltage is usually punch through of the electrolyte resulting in catastrophic failure of the capacitor a short. 1 2 4 but for basic power supplies lc designs are less popular than rc as the inductors needed for the filter to work efficiently at 50 to 120hz need to be large and expensive. The context is a charger circuit more specifically its power supply unit.

Capacitors for ac applications range from high voltage oil filled devices such as the one shown in figure 5 5 to low voltage high capacitance devices of the type typically found in power. Given a diode bridge rectifier that is connected on one set of terminals to the mains via a filter circuit and on the other side to two electrolytic capacitors connected in series. For example a 10 ripple in a 5 v power supply means that the actual output voltage varies by 0 5 v. 3 exposure to excessive voltage beyond the rated voltage of the capacitor.

For a typical 5 v power supply a 2 200 μf electrolytic capacitor will do the job. Other times the power supply will kick on as normal and deliver significant power into the shorted tantalum capacitor. Why the capacitor in your power supply filter is too big january 21 2016 by david williams the job of the capacitor in the output filter of a dc power supply is to maintain a constant dc value by removing as much power ripple as possible. Simple shunt capacitor filter reduces the ripple voltage but increases the current through the diode.

Capacitors are reactive elements which make them suitable for use in analog electronic filters. Gideon analytical laboratories received an areovox z26p6045m21 45uf 600v capacitor for failure analysis. Filter capacitors are used for. Inside most capacitors there are two metal plates separated by a non conducting substance dielectric.

Parallel to each capacitor are two discharge resistors. Capacitors are passive two terminal electrical components used to store electricity in an electric field. If the capacitor is used as a power supply filter and the capacitor. The bigger the capacitor the lower the resulting ripple voltage.

In this case the results are much more spectacular with the tantalum capacitor often literally catching on fire and blowing up. Because these capacitors have a dc value they are actually storing a lot of energy that never gets used. Either lc or rc low pass filters can be used to remove the ripple remaining after the reservoir capacitor. L c filters power supply filters.

And failure of the capacitor. 1 2 3 is more efficient and gives better results than the rc filter shown in fig.