VOLTAGE DOUBLER : drop in current?

Ziggy · 12th February 2009, 05:45 AM

Fellow experts

I have searched the forum, and ''googled''.......is it correct that when using a transformer with a 200ma capacity, a voltage doubler circuit in place of a normal SS rectifier configuration, will only provide HALF of that available current(100ma max)?

Any help would be appreciated.

DigitalJunkie · 12th February 2009, 05:57 AM

In short,Yes.

aardvarkash10 · 12th February 2009, 06:23 AM

combine Ohms Law with the Conservation of Energy principle and there you are. In fact, there you are, less a bit of energy losses...

Ziggy · 12th February 2009, 11:41 AM

Bummer !!.........can't get something for nothing eh?
Thanks For your help guys.

Eli Duttman · 12th February 2009, 03:30 PM

Quote:

Originally posted by Ziggy
Bummer !!.........can't get something for nothing eh?
Thanks For your help guys.

Recently, SY expounded on the 3 Laws of Thermodynamics. I submit his explanation reduces to a form of Murphy's Law. "You can't win, you can't break even, and you can't quit the game."

Seriously, in cap. I/P filter PSUs (including voltage multipliers), approx. 1/2 of the rectifier winding's AC RMS rating is available as DC. In a multiplier, that available current is distributed across each of the steps. So, in a doubler PSU plan on 1/4 of the power trafo RMS rating as DC current.

Ziggy · 13th February 2009, 04:11 AM

gotta get me a new power transformer.Meh!......it's only money.

Wavebourn · 13th February 2009, 04:57 AM

Also, you will need twice more of capacitance since ripple frequency will be twice lower.

Sch3mat1c · 13th February 2009, 05:53 AM

Actually, it's less than half, because the peak-to-average ratio is very high. Besides, you'll get poor performance if you use a doubler that close to the winding's rating. Doublers require low impedance to obtain reasonable regulation.

Tim

ray_moth · 13th February 2009, 06:51 AM

Yes, that probably explains why the Cit II power tranny high voltage secondary winding has a low impedance of only 11 ohms or so.

Ziggy · 13th February 2009, 10:45 AM

Yet, I once saw a Japanese valve amplifier circuit book with dozens and dozens of schematics - MOST were voltage doublers

.......so what gives if there are so many downfalls

12th February 2009, 05:45 AM	#1
Ziggy Account Disabled Join Date: Jul 2004 Location: West Australia	VOLTAGE DOUBLER : drop in current? Fellow experts I have searched the forum, and ''googled''.......is it correct that when using a transformer with a 200ma capacity, a voltage doubler circuit in place of a normal SS rectifier configuration, will only provide HALF of that available current(100ma max)? Any help would be appreciated.

12th February 2009, 06:23 AM	#3
aardvarkash10 diyAudio Member Join Date: Mar 2007 Location: Auckland, NZ	yep! combine Ohms Law with the Conservation of Energy principle and there you are. In fact, there you are, less a bit of energy losses... __________________ Yes, conservatism thrives on low intelligence and poor information. But the liberals in politics... continue to back off, yielding to the supremacy of the stupid. It's turkeys all the way down. - George Monbiot, guardian.co.uk, 6 Feb 2012

13th February 2009, 04:57 AM	#7
Wavebourn diyAudio Member Join Date: Sep 2006 Location: Pleasant Hill, CA	Also, you will need twice more of capacitance since ripple frequency will be twice lower. __________________ The devil is not so terrible as his mathematical model! Wavebourn: We Create Creativity!

13th February 2009, 05:53 AM	#8
Sch3mat1c diyAudio Member Join Date: Jan 2003 Location: Milwaukee, WI	Actually, it's less than half, because the peak-to-average ratio is very high. Besides, you'll get poor performance if you use a doubler that close to the winding's rating. Doublers require low impedance to obtain reasonable regulation. Tim __________________ See my Electronics webpage -- the home of Vacuum Tube Drag Racing. The key to being a successful Audiophile: "I reject your reality and substitute my own!"

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

12th February 2009, 05:57 AM	#2
DigitalJunkie diyAudio Member Join Date: Apr 2003 Location: Portland,Oregon Blog Entries: 4	In short,Yes.

12th February 2009, 11:41 AM	#4
Ziggy Account Disabled Join Date: Jul 2004 Location: West Australia	Bummer !!.........can't get something for nothing eh? Thanks For your help guys.

13th February 2009, 04:11 AM	#6
Ziggy Account Disabled Join Date: Jul 2004 Location: West Australia	gotta get me a new power transformer.Meh!......it's only money.

13th February 2009, 06:51 AM	#9
ray_moth diyAudio Moderator Emeritus Join Date: Jan 2004 Location: Jakarta	Yes, that probably explains why the Cit II power tranny high voltage secondary winding has a low impedance of only 11 ohms or so.

13th February 2009, 10:45 AM	#10
Ziggy Account Disabled Join Date: Jul 2004 Location: West Australia	Yet, I once saw a Japanese valve amplifier circuit book with dozens and dozens of schematics - MOST were voltage doublers .......so what gives if there are so many downfalls

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Need help with voltage doubler	Lingwendil	Power Supplies	6	22nd April 2009 12:15 AM
Voltage Doubler	jwatts	Tubes / Valves	3	2nd January 2009 12:13 AM
using voltage drop to calculate current	cbutterworth	Power Supplies	2	3rd September 2007 01:21 AM
negative voltage doubler for ccs	Jaap	Tubes / Valves	6	6th February 2006 05:32 AM
Voltage doubler	Baard	Solid State	28	17th January 2005 04:46 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read