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Function Of Bridge Rectifier In Electronic Circuit

By Jestine Yong on June 26, 2007

The purpose of a bridge rectifier in electronic circuit is to convert the ac voltage (wave) into Dc voltage. Usually it is located near the ac supply area. It can come in the 4 separate diodes arrangement or in a single package as seen from the photo. The specification that you need to know for a bridge rectifier are the peak reverse voltage (PRV) and the ampere. How do we know the spec of a bridge rectifier? By looking at part number printed on the body. The part number usually start with KBLXXX and you have to search a data book to look for the specification. Always replace the bridge rectifier with the same or a higher specification.

If you have the time, you can always join four separate diodes to form a bridge rectifier. Use the general purpose part number such as the 1N4007 to make a bridge and sometime this rectifier can even work better than the original one.

Whenever a fuse open in electronic equipment, you must always check the bridge rectifier. Chances is high that the bridge may go shorted too. If you experience enough, you may check the bridge rectifier while it is still on board. If you are a beginner, i suggest that you remove the bridge and test it with you multimeter. In Monitor repair,usuallly a replacement of a fuse and a bridge rectifier will restore to normal operation.

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11 Comments

chrisz

July 25, 2010 at 7:51 am

I'm trying to repair my power board on an Insignia model inc2325. My Lcd Tv will not turn on. The capacitors are all visually fine and power is running to the board. The fuse on the board is also good.The only way I'm getting the Tv to power up is by heating the bridge rectifier with a blow dryer. I'm not at all an expert at fixing lcd tv's. I've brought the Lcd tv to a repair man but he does not Know what the problem is and refused to spend anymore time on it. I've also purchased a board that was similar, but some of the components are different and that does not work. Do you think that the bridge rectifier has to be changed? Any input would be appreciated.

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admin

July 26, 2010 at 7:59 am

HI Chrisz,

If there is no power output from the power supply and when you heat up the bridge and the power came back then most likely the bridge or the corresponding component may have problem. Since bridge rectifier is cheap then you should replace and retest to see how it goes. If after replacement still with the same symptom then i suggest that you check the surrounding components. Make sure the power IC is receiving good supply voltage

Jestine

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Karabo

May 5, 2011 at 9:44 am

Straight explanation it is thanks...

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Eddy Edward

May 3, 2013 at 11:01 pm

What other functions can the Bridge Rectifier perform other than conversion of AC(wave) into DC voltage in a circuits?

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- Jestine Yong
  
  May 6, 2013 at 3:01 pm
  
  HI Eddy,
  
  Good question. So far in my daily repair job bridge was used in the conversion of AC into DC. If you check out the link below it has some other functions:
  
  http://www.cnczone.com/forums/product_announcements_manufacturer_news/123694-use_bridge_rectifier_function_bridge_rectifier.html
  
  Jestine
  
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Meshal

November 21, 2014 at 5:36 am

Dear Jestin,

I have defective bridge rectifier 4 A 600 V on my piwer supply . Is it safe if i replace it with higher such as 8 A 800V ? . What if i replace it with lower rate?

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- admin
  
  November 21, 2014 at 10:27 am
  
  Hi meshal,
  
  Yes you can replace with the higher volt and amp and not the lower spec one. if you replace with lower spec component chances for it to blow would be very high.
  
  Jestine
  
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sunFD

December 11, 2015 at 6:07 pm

Thanks sir for the tutorial.
My deowoo crt tv 28 inches makes noise from the crt tube when i power it on and the picture is distorted when there is a bright scene. The picture tend to get brighter with white display and then power down. Even now it just began to flip when power on with noise from the tube area. I change the hot then when i power it on it just blow the fuse. What can i do next?

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- Jestine Yong
  
  December 12, 2015 at 5:52 pm
  
  HI Sunfd,
  
  In your case, in can be due to bad flyback or even bad tube. Why do you change the HOT when the hot is working normally? Did you change with the same part number? The main fuse blow or the B+ protection fuse? Have you checked if the B+ supply voltage good and stable?
  
  Jestine
  
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dalganjan kurre

February 28, 2017 at 9:32 am

sir can i replace rl207 to fr207?

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- Jestine Yong
  
  March 1, 2017 at 9:28 pm
  
  Hi Dalganjan,
  I have not used this number before for replacement. There is not much different in the spec and guess you have to test it out.
  
  Jestine
  
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