diode rectifier ratings

redrabbit · 12th November 2006, 01:43 AM

a PSU for class A/B 80w amp....full wave rectifier question:

If the design calls for a 35a bridge, but I want to use 4 diode rectifiers instead, what amperage should each diode be?
Is it:
four 8amp diodes = 32amps?
......or should each diode be 35a.....naw, they'ld be huge

??

=RR=

SY · 12th November 2006, 02:41 AM

35A per. Sorry.

sivan_and · 12th November 2006, 02:47 AM

15 amp each diode...whats the VCC ? supply voltage

redrabbit · 12th November 2006, 03:18 AM

Quote:

Originally posted by sivan_and
15 amp each diode...whats the VCC ? supply voltage

it's for a Cap Filter supply, dual polarity, transformer is 28-0-28v, @2.7amps.
115v primary.
Toriodal.

=RR=

sivan_and · 12th November 2006, 06:41 AM

28-0-28v, @2.7amps....its too small VA for 80watts class AB

AndrewT · 12th November 2006, 06:28 PM

Hi,
this is going to sound completely opposite to my usual play safe philosophy but let's just describe what is in my Sugden P128s (about 180W into 8r).

Each 52Vac winding passes through a diode bridge formed from four 1n5404s, feeding 20mF charged to 72Vdc. Iq=300mA.

They have never gone pop and there is no soft start.
So the dual polarity supply +-72Vdc is fed from 8 diodes as two bridges in series, the centre point being PSU 0volts. Yes, 3A diodes seem to be very reliable.

redrabbit · 12th November 2006, 08:13 PM

Quote:

Originally posted by sivan_and
28-0-28v, @2.7amps....its too small VA for 80watts class AB

You are correct, I was exagerating the specs a bit.

AndrewT....you rebel, life on the edge is sweet !

I'll most likely use the overkill 35a bridge, but was hoping to use four 6 amp diodes I have........they fit better in the enclosure.
Oh well.

=RR=

redrabbit · 13th November 2006, 01:33 AM

It still has me thinking.....
What is in a 35a encapsulated bridge rectifier ?

Are there really four 35a diodes in there?

......or are the diodes lower value, and the encapsulation/termination-package qualifies it to become rated at a higher amperage, compared to individual (discreet) diodes ?

=RR=

peranders · 13th November 2006, 05:33 AM

A 35 A rectifier bridge consists of four 35 A diodes.

Most bridges are made for 50/60 Hz applications if you mean by that "lower value".

You can also build a rectifier bridge with discrete diodes, then you can choose the diodes with taste which means faster diodes.
Example here:
http://home5.swipnet.se/~w-50674/hif...0_overview.jpg
http://home5.swipnet.se/~w-50674/hif...r0_topview.jpg

12th November 2006, 01:43 AM	#1
redrabbit diyAudio Member Join Date: Oct 2004	diode rectifier ratings a PSU for class A/B 80w amp....full wave rectifier question: If the design calls for a 35a bridge, but I want to use 4 diode rectifiers instead, what amperage should each diode be? Is it: four 8amp diodes = 32amps? ......or should each diode be 35a.....naw, they'ld be huge ?? =RR=

12th November 2006, 02:41 AM	#2
SY diyAudio Moderator Join Date: Oct 2002 Location: Chicagoland Blog Entries: 1	35A per. Sorry. __________________ If there's a sucker born every minute, where do the rest of them come from?

12th November 2006, 02:47 AM	#3
sivan_and diyAudio Member Join Date: Dec 2004 Location: Dxb / India	15 amp each diode...whats the VCC ? supply voltage __________________ SivanandBalan

12th November 2006, 06:41 AM	#5
sivan_and diyAudio Member Join Date: Dec 2004 Location: Dxb / India	28-0-28v, @2.7amps....its too small VA for 80watts class AB __________________ SivanandBalan

13th November 2006, 05:33 AM	#9
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	A 35 A rectifier bridge consists of four 35 A diodes. Most bridges are made for 50/60 Hz applications if you mean by that "lower value". You can also build a rectifier bridge with discrete diodes, then you can choose the diodes with taste which means faster diodes. Example here: http://home5.swipnet.se/~w-50674/hif...0_overview.jpg http://home5.swipnet.se/~w-50674/hif...r0_topview.jpg __________________ /Per-Anders (my first name) or P-A as my friends call me Tube Buffered Gainclone in work \|Thread


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12th November 2006, 06:28 PM	#6
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, this is going to sound completely opposite to my usual play safe philosophy but let's just describe what is in my Sugden P128s (about 180W into 8r). Each 52Vac winding passes through a diode bridge formed from four 1n5404s, feeding 20mF charged to 72Vdc. Iq=300mA. They have never gone pop and there is no soft start. So the dual polarity supply +-72Vdc is fed from 8 diodes as two bridges in series, the centre point being PSU 0volts. Yes, 3A diodes seem to be very reliable.

13th November 2006, 01:33 AM	#8
redrabbit diyAudio Member Join Date: Oct 2004	It still has me thinking..... What is in a 35a encapsulated bridge rectifier ? Are there really four 35a diodes in there? ......or are the diodes lower value, and the encapsulation/termination-package qualifies it to become rated at a higher amperage, compared to individual (discreet) diodes ? =RR=

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