
Home  Forums  Rules  Articles  The diyAudio Store  Gallery  Blogs  Register  Donations  FAQ  Calendar  Search  Today's Posts  Mark Forums Read  Search 

Please consider donating to help us continue to serve you.
Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving 

Thread Tools  Search this Thread 
20th April 2012, 07:58 AM  #1 
diyAudio Member
Join Date: Apr 2012

±45v lm317?

20th April 2012, 08:18 AM  #2  
diyAudio Member

Quote:
An example: for output of 11.25V, you know that there will be 10V across R2+Rv1. (11.25  1.25). 10V is 8 times 1.25V on R1 so R2 + Vr1 = 8 times R1 = 8 times 220 = 1720 ohms. For your 45V you know on R2 + Vr1 is 451.25 = 43.75V, so R2 + Vr1 = 43.75/1.25 * 220 = 7.7k.... For the 45 you can use an LM337 but the calculation is the same. BTW This is also in the datasheet, very simple, you could easily find that yourself without worrying what is true or not. Datasheets are your friend! ;) jan didden
__________________
I won't make the tactical error to try to dislodge with rational arguments a conviction that is beyond reason  Daniel Dennett Check out Linear Audio Vol 7! Last edited by jan.didden; 20th April 2012 at 08:20 AM. 

20th April 2012, 08:22 AM  #3 
diyAudio Member
Join Date: Jan 2006
Location: Ireland

Plus there are loads of online calculators to make it even easier. There are also LM317ht that can do 57v

20th April 2012, 08:28 AM  #4  
diyAudio Member
Join Date: Apr 2012

Quote:
thany you very much ,i see. 

20th April 2012, 08:38 AM  #5 
diyAudio Member
Join Date: Sep 2007
Location: Hangzhou  Marco Polo's 'most beautiful city'. 700yrs is a long time though...
Blog Entries: 98

Beware the inputoutput voltage limit
For any input voltage above 40V, there's no short circuit protection with this device  I've seen at least one explode, so be very wary of shorting the output. On powerup transients too its possible to exceed the abs max.
__________________
It doesn't have to take the form of a conspiracy, rather a consensus... James H Kunstler 
22nd April 2012, 08:47 AM  #6 
diyAudio Member
Join Date: Jan 2001
Location: Denmark

LM783?
/U. 
22nd April 2012, 09:08 AM  #7 
diyAudio Member
Join Date: Nov 2011
Location: UK

You'd be better off building a regulator using discrete components at that voltage.
Have a look at http://www.kkpcb.com for some ideas. 
22nd April 2012, 09:29 AM  #8 
diyAudio Member
Join Date: Nov 2011
Location: UK


22nd April 2012, 02:00 PM  #9 
diyAudio Member
Join Date: Apr 2012

agree with KatieandDad
You'd be better off building a regulator using discrete components at that voltage. 
22nd April 2012, 05:29 PM  #10 
diyAudio Member

LM317 can only handle about 1,5A so be carefull on that part, if you need higher current than you will need to add a power tranzistor on it, but as the other have sayd it would be better with zenner diodes and a few transistors to supply the needed current, it would be much safer as you can add the protection you want/need.

Thread Tools  Search this Thread 


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Its only need +50V for +/45V outputs.  ontoaba  Solid State  47  24th January 2011 10:29 AM 
Power Trans, 45V045V  pistoljoe  Swap Meet  1  15th April 2008 10:39 AM 
WTB 625VA, 230Vac, 2 x 45V  Pocoyo  Swap Meet  8  28th May 2007 04:39 PM 
Where are all the 300VA 45v toroids at?  ShinOBIWAN  Solid State  9  15th May 2007 07:52 PM 
What would happen with a 45V transformer???  camshaft  Chip Amps  3  27th February 2007 06:04 PM 
New To Site?  Need Help? 