9v to 5v converter using lm7805!

Discussion in 'General Electronics Chat' started by zaman999, Jan 19, 2012.

  1. zaman999

    Thread Starter New Member

    Jan 29, 2011
    26
    0
    Hi! I want to make a 9V to 5V, dc-dc converter circuit using LM7805.I have the schematic attached.

    My doubt is how do i make the selection of the capacitors C1 and C2?

    I tried simulating with different values like 100nF,10nF and i got the same output of 5V. So how do we select the values of these capacitors?

    Regards,
    Zaman.
     
  2. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    657
    The capacitors are there to keep the 7805 from oscillating. They don't affect the DC output voltage.
    Use the values recommended in Fig. 10 in the datasheet.
     
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  3. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,771
    971
    C1=.33uF
    C2=.1uF
    per the datasheet.. The caps are just for noise/stability/transient response.. All of which you probably aren't simulating for.
     
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