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Farshid Jafari Harandi
05/27/05 03:55
Read: 1944 times
Sweden
Gothenburg


 
#93967 - Info on Murata Inductors for LC filter ?
Hi Dear members of 8052.com

I am having new problems with my DCCS project which disscused earlier here : http://www.8052.com/forum/thr...read=72808 .problems appeared mostly after changing the spark plugs and some other hardware upgradings . (resistor spark plugs has been changed with no resistor plugs)

after all of this i decided to implement the LC filter on the input line of the three board (Relay driver board , 7 segments driver board,Main board).

The problem that i didn't implmented this so far was the trouble i've had to find a frrite bead like BL02RN2 which is mentioned http://www.8052.com/faq.phtml?FAQ=93 by dear Prahlad , everytime i go to the electronic market here, they want me to tell them a number based on Hanry and the amperage rating of the inductor.(this is all about buying a wound inductor ,i don't have all of the suitable instruments to wound one myself)

1- so here is my question , what type of inductor is suitable for filtering supply noise .(Toroidal ,EI core ,Axial ,Radial ,Etc)

2- how should be the value of inductor calculated ,above of what frequency should be filtered , is it have to be calculated like this (based on Dear Kai's suggestion here : http://www.8052.com/forum/read.phtml?id=53375 ):
T=5 mH * 200 uF = 1 uSecond
F=1/T= 1 MHZ
if i was right,this should filter frequencies above 1Mhz ?
here is the picture of the ferrites which i've bought yesterday , maybe these could be helpful :
http://www.8052.com/users/farshidjh/IMG_3883.JPG

3- i cannot summary a final answer in my mind , in this project 'where the +5v enters the board' should be right after the LM7805K regulator ,didn't i have also to use a filter on the Car Baterry input to the board ?

4- i have 15V varistors in my components. does adding this component has a benefit in noise suppresion ?

i have read every discussion related to noise and ground potnetial problems and random resetes since i've membered here (2001), but due to my lack of knowledge in analog design and loosy electronic market here,i wasn't able to implement all of them to my designs.
my big thanks to everyone who spend their valuable time and share their experience with us.

P.S. : Still no Boom releated to the fuel tank gauge ! ;)

Wish you all a good weekend
Farshid J.H.


List of 22 messages in thread
TopicAuthorDate
Info on Murata Inductors for LC filter ?      Farshid Jafari Harandi      05/27/05 03:55      
   Ground routing and filtering        Kai Klaas      05/27/05 04:57      
      Examples of soft ferrites      Kai Klaas      05/27/05 05:07      
         good link      Farshid Jafari Harandi      05/27/05 17:13      
      Ground routing      Mehdi      05/27/05 07:24      
         Ground routing techniques      Kai Klaas      05/31/05 04:34      
      Ferrite on cables and filtering      Farshid Jafari Harandi      05/27/05 17:05      
         Answers...        Kai Klaas      05/31/05 05:18      
            many of my questions are answered ! :)      Farshid Jafari Harandi      05/31/05 12:16      
               Long lines      Kai Klaas      06/01/05 08:50      
                  the other reason      Erik Malund      06/01/05 09:24      
                     Buffers good !      Farshid Jafari Harandi      06/01/05 17:18      
                  my next PCB would be way much better !      Farshid Jafari Harandi      06/01/05 17:18      
   BL02RN2 in Tehran      Payam Soltany      05/27/05 20:10      
      thanks a thousand dear payam      Farshid Jafari Harandi      05/28/05 09:28      
         On-Board Type EMI Suppression Filters      Payam Soltany      05/28/05 18:37      
         Basics of EMI Filters      Payam Soltany      05/28/05 18:38      
         More...      Payam Soltany      05/28/05 18:40      
         Tell me when it's enough        Payam Soltany      05/28/05 18:43      
            you're doing a favor for me!      Farshid Jafari Harandi      05/28/05 19:49      
               Not all available in Tehran probabely//      Payam Soltany      05/28/05 20:40      
               BL02RN2 Datasheet      Payam Soltany      05/28/05 21:13      

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