Fast switching bridge rectifier

Discussion in 'The Projects Forum' started by soda, Feb 24, 2010.

  1. soda

    Thread Starter Active Member

    Dec 7, 2008
    174
    13
    Hi to all members,
    Please tell me if it's bad or ok to use a fast switching bridge rectifier on a normal LM317 supply. What trouble's me is that I'm only pulling a 160mA from the lm317 and the temp went up to 70 degrade Celsius.
    I have a lot of these bridges and wanted to see if i cant make use of it.
    Thanks soda
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,347
    Hello,

    Can you post a schematic?
    What is the input voltage and what is the output voltage and the current draw?

    Greetings,
    Bertus
     
  3. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
    1,066
    The temperature rise of the LM317 has nothing to do with the rectifier; it has everything to do with the power dissipation in the regulator, which is the product of the current through the regulator multiplied by the voltage difference between the regulator input and output.
     
  4. soda

    Thread Starter Active Member

    Dec 7, 2008
    174
    13
    Mike, thanks for the advise. So if i look what you say, then there's nothing wrong with using the fast switching rectifier, it's more the regulator. I'm going to put the regulator on a bigger heat sink.
    Bertus, i know there's nothing wrong with the diagram of the power supply, but i just thought the 160mA was not mush. The lm317 can handle up to 1,5amp. I think the bigger heatsink will do the job.

    Thanks for the help, guys
    Soda
     
  5. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
    1,758
    98
    It can only supply the full 1.5A if the input voltage is only a few volts above the regulated voltage. What are the input and output voltages?
     
  6. soda

    Thread Starter Active Member

    Dec 7, 2008
    174
    13
    Hi blueroom
    My input voltage is 26vac and my output is 15v dc. I use a larger heatsink for the LM317 and it's running mush cooler now.
    Thanks for the reply
     
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