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I have a bad 10 microfarad capacitor 400V but can not get a replacement.

Can I use 22 microfarads 400V instead?

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    \$\begingroup\$ What is the capacitor used for, e.g. is it a smoothing capacitor, an AC coupling capacitor, part of a timing circuit, or maybe something else? \$\endgroup\$ – Andrew Morton Apr 17 at 12:32
  • \$\begingroup\$ @AndrewMorton 400V cap for timing? \$\endgroup\$ – Huisman Apr 17 at 12:34
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    \$\begingroup\$ Please show a schematic. Without we can't give a reliable/safe advise. A capacitor has more parameters than just size and voltage rating. \$\endgroup\$ – Huisman Apr 17 at 12:35
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    \$\begingroup\$ You shouldn't replace X1/Y2 capacitors by X2/X2 capacitors for example. You should consider the ESR... etc \$\endgroup\$ – Huisman Apr 17 at 12:43
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    \$\begingroup\$ If you have two 22µF caps and you connect them in series - the series combination would have a capacitance of 11µF - pretty close to your original capacitor. Depending on the application you may or may not need to do this. \$\endgroup\$ – scorpdaddy Apr 17 at 14:32
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It will depend on the application... A higher capacitance usually comes with a higher ESR (equivalent series resistance) and obvously induces a higher time constant when involved in resonant/ filtering circuit.

But by looking at the capacitance and voltage rating of your capacitor, I am assumming it is some kind of mains/power supply filtering capacitor. In this case, the +12uF difference should not cause any harm.

Be carefull to put the new one the right way around (I am pretty sure you are faced with an electrolytic capacitor, which has a polarity).

To summarize, it will most lokely work just fine.

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  • \$\begingroup\$ Yeah..thanks so much. you have cleared my doubts \$\endgroup\$ – fai cornelius Apr 17 at 13:12
  • \$\begingroup\$ @fai - If this is for a tube amplifier with a tube rectifier and you add too much capacitance, you could blow the rectifier from too much inrush current. \$\endgroup\$ – schadjo Apr 17 at 17:11
  • \$\begingroup\$ Just saw it's for a decoder board. Probably no problem to sub the 22 µF cap. \$\endgroup\$ – schadjo Apr 17 at 17:15

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