stealth17 Posted October 2, 2005 Report Share Posted October 2, 2005 Does the physical size of a capacitor matter? Like a tiny 16v 1000uf just as good as a large 16v 1000uf? Quote Link to comment Share on other sites More sharing options...
audioguru Posted October 2, 2005 Report Share Posted October 2, 2005 A larger new capacitor has a better ripple-current rating.If the capacitor is used as the rectifier filter in a high current power supply, It will have a high ripple voltage across it because its charging and discharging currents are high. A small capacitor will overheat and fail. You might need to use a large capacitor with a higher voltage rating to find one with a high ripple-current rating.Large old capacitors have about the same ripple-current ratings as small new ones, so don't just select a larger size. Quote Link to comment Share on other sites More sharing options...
stealth17 Posted October 2, 2005 Author Report Share Posted October 2, 2005 A larger new capacitor has a better ripple-current rating.If the capacitor is used as the rectifier filter in a high current power supply, It will have a high ripple voltage across it because its charging and discharging currents are high. A small capacitor will overheat and fail. You might need to use a large capacitor with a higher voltage rating to find one with a high ripple-current rating.Large old capacitors have about the same ripple-current ratings as small new ones, so don't just select a larger size.cool, thanks. Ive read that its not a real good idea in most cases to go over 150% original capacitance. The voltage doesn seem to matter either. Like I can use a 25v cap in place of a 10v cap without problems. Also Ive read that the low-ESR caps are the ones rated for 105c (usually).Sound all up to par? Quote Link to comment Share on other sites More sharing options...
prateeksikka Posted October 7, 2005 Report Share Posted October 7, 2005 hi audioguru !sorry for the interruption but i would say that a surge in the supply would be a more appropriate word than ripple.Although i agree with u that a large cap has higher rating for surges. Quote Link to comment Share on other sites More sharing options...
audioguru Posted October 7, 2005 Report Share Posted October 7, 2005 Hi Prateek,Large value capacitors are usually used as filters following a full-wave rectifier in high current equipment. Surges are infrequent but ripple current occurs continuousy, on every half-cycle of the mains. Because the load current is high, the capacitor's ripple current is also high which overheats small capacitors. Quote Link to comment Share on other sites More sharing options...
prateeksikka Posted October 8, 2005 Report Share Posted October 8, 2005 So should we go for large caps specially in filters.In all ckts i have seen they are generally the largest components.A huge giant of a small value. It looks as a pole in a small circuit. ;D Quote Link to comment Share on other sites More sharing options...
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