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Post by buelligan on Jan 25, 2009 7:46:01 GMT
I'm just curious about why there are 63V caps in the X-10 v3 power supply when there is only +/- 12V coming into the unit.
The X-CAN v3 has 35V caps and uses the same input voltage.
Thanks for any info,
Buelligan
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robertkd
Been here a while! 
Electronics Engineer from sunny Queensland
Posts: 111
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Post by robertkd on Jan 25, 2009 9:12:23 GMT
It's not a problem, generally higher voltage ratted capacitors have better ripple current ratting.
Robert
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Deleted
Deleted Member
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Post by Deleted on Jan 25, 2009 9:17:05 GMT
buelligan Don't forget that the capacitor rating would need to be at least 35V because of the voltage doubler used to step up the voltage required for the anodes of the valves. Robert's answer is also correct, although I wonder which bit of gear he ratted the capacitors from ?  SandyK |
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robertkd
Been here a while!
Electronics Engineer from sunny Queensland
Posts: 111
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Post by robertkd on Jan 25, 2009 9:57:49 GMT
mmm oh um various bits and pieces ;D
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Post by buelligan on Jan 25, 2009 21:42:58 GMT
I guess my question is, would it be safe and beneficial to use higher capacitance (thus more stable voltage), lower voltage (more capacitance for the physical dimension) 35V caps in the X-10 v3 (as in the X-CAN v3, which also uses valves and 35V rated caps)?
Also, as I always seem to learn something from Alex K., how do you step up a voltage without a transformer, or at least an inductor?
Thanks everyone,
Buelligan
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robertkd
Been here a while!
Electronics Engineer from sunny Queensland
Posts: 111
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Post by robertkd on Jan 25, 2009 22:22:29 GMT
Ok as for selection of capacitors a few basics, look for higher temperature ratting 105 deg C are usually only a little bit more expensive but tend to last a lot longer. the working voltage is a function of the thickness of the dielectric, so lower voltage units tend to be smaller physically or for similar size have a larger capacitance! But the trade of is less margin especially in power supplies where spikes and variations in mains voltage can lead to somewhat higher voltages being developed. Higher voltage capacitors usually have better ripple current rating and lower ESR both are desirable attributes for a power supply and sometimes better then having simply a larger capacitance. Also be aware ripple current is usually given for high frequencies not mains related 50/60Hz (100/120hz) specially designed filter capacitors have ripple current rating specified at 100/120Hz. I tend to go for 105 deg units usually go for the next higher voltage if physically suitable other wise try to have at least 20% margin for working voltage. look for higher ripple current rating and lowest ESR units. basic voltage doubler en.wikipedia.org/wiki/Voltage_doubler voltage multipliers,.. en.wikipedia.org/wiki/Voltage_multiplier |
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