Conversion of 9-0-9 AC to 3V DC output voltage..

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harisharanyp

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I want to convert 230 ac voltage to 3v dc using 9-0-9 transformer at the input side..How to rig-up this rectifier circuit..Is it necessary to use 7805 ic ?? Using this 3v dc to power the xbee module..plz help
 

harisharanyp said:
I want to convert 230 ac voltage to 3v dc using 9-0-9 transformer at the input side..How to rig-up this rectifier circuit..Is it necessary to use 7805 ic ?? Using this 3v dc to power the xbee module..plz help
Click to expand...


Hi harisharanyp and Welcome to EDABoard,

You can use 3,3V voltage regulators, no need for 5V regulator if you need 3V.

What you mean under "input side" ?

:wink:
 
Thank you for your reply.Input side means input of the rectifier.Did you mean three 3v voltage regulators? if so then please give some more info about the 3v regulator ic. Waiting for your reply.
 

 

harisharanyp said:
Thank you arunava7.. Can you help me out with the circuit using LM317?
Click to expand...


You can find application samples (examples of circuits) in manufacturer part datasheet. Datasheets you can find on links in post #5, just click on info link or check manufacturer web site.

:wink:
 
You could use a bridge rectifier some smoothing capacitors and a voltage regulator. You need a 3V voltage regulator not a 7805. You will need to be careful on thermal management as the bridge and regulator may well get hot when reducing from rectified 9V (nearly 13Vdc) down to 3V dc, rather depends on you current requirements.

Sorry posted this a long time after looking at the original posting so missed that others are already helping, I haven't yet read their posts.
 
Actually, I've found it difficult to find a good 3.3V voltage regulator as such...I've used mostly LM317's and the results are fair
 
Use bridge rectifier at transformer secondary like W02G. The use of 7805 is not necessary and its output will be 5V not 3V. Also, its efficiency is less than 60%, u will end up wasting power but it will cost less and good for testing purposes, instead use switching buck regulator, it will give efficiency of 98%, and advisable to use in applications.
While using buck regulator, make sure the surge currents meets the xbee module specification and do add big electrolytic cap of 2200uF for heavy surge requirement of module if any.
 
tpetar said:
You can find application samples (examples of circuits) in manufacturer part datasheet. Datasheets you can find on links in post #5, just click on info link or check manufacturer web site.

:wink:
Click to expand...
ok..Thank you.will search about it and reply to you.

- - - Updated - - -

arunava7 said:
Actually, I've found it difficult to find a good 3.3V voltage regulator as such...I've used mostly LM317's and the results are fair
Click to expand...


Link shows doesn't match any document..plz check the link.Thank you.
 
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    tpetar

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