quick Q on power supply caps

theChris · 25th October 2003, 09:15 AM

ok, i have 1 question on power supply capacitors and that is on the required voltage for use. i have a 48Vct transformer that i plan to use, i was planning on useing 50V rated caps with the transformer (48Vct, 7A). will this work or will i need to move to a larger voltage rating. i will also have a noise filter before the amplifer. i will test that.

in any case any help would as always be appreciated.

Sch3mat1c · 25th October 2003, 04:39 PM

Will you be using the CT, as a +/- power supply? If so, then yes; each pole will have only 33V across it.

Tim

theChris · 25th October 2003, 06:34 PM

ok, thanks. it will be used as mentioned above. ok, i was just wondering if there was some kind of de-rating that was used.

EE_Mark · 5th November 2003, 05:50 AM

If the transformer is 48 VCT then the nominal AC voltage on each side will be 24 volts. Multiply that by the square root of 2 (1.414) and you get 33.9 volts. The voltage may be lower when the transformer is loaded but unloaded with a voltage surge (assume a voltage surge of 10% or more for derating purposes) and now you're looking at ~ 40 volts. A 50 volt capacitor (per rail) would be perfect for that situation.

25th October 2003, 09:15 AM	#1
theChris diyAudio Member Join Date: Dec 2001 Location: SIUE, Illinois, USA	quick Q on power supply caps ok, i have 1 question on power supply capacitors and that is on the required voltage for use. i have a 48Vct transformer that i plan to use, i was planning on useing 50V rated caps with the transformer (48Vct, 7A). will this work or will i need to move to a larger voltage rating. i will also have a noise filter before the amplifer. i will test that. in any case any help would as always be appreciated. __________________ if only it could be used for good, not evil...

25th October 2003, 04:39 PM	#2
Sch3mat1c diyAudio Member Join Date: Jan 2003 Location: Milwaukee, WI	Will you be using the CT, as a +/- power supply? If so, then yes; each pole will have only 33V across it. Tim __________________ Seven Transistor Labs Projects and Resources

25th October 2003, 06:34 PM	#3
theChris diyAudio Member Join Date: Dec 2001 Location: SIUE, Illinois, USA	ok, thanks. it will be used as mentioned above. ok, i was just wondering if there was some kind of de-rating that was used. __________________ if only it could be used for good, not evil...

5th November 2003, 05:50 AM	#4
EE_Mark diyAudio Member Join Date: Nov 2003 Location: Los Angeles	Capacitor Voltage If the transformer is 48 VCT then the nominal AC voltage on each side will be 24 volts. Multiply that by the square root of 2 (1.414) and you get 33.9 volts. The voltage may be lower when the transformer is loaded but unloaded with a voltage surge (assume a voltage surge of 10% or more for derating purposes) and now you're looking at ~ 40 volts. A 50 volt capacitor (per rail) would be perfect for that situation. __________________ Mark

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