Voltage regulator

Discussion in 'General Electronics Chat' started by abhilashsukumari, Mar 21, 2013.

  1. abhilashsukumari

    Thread Starter New Member

    Mar 14, 2013
    Hello all,

    I am doing a project where I have to develop a circuit which is supposed to give an output voltage of +5v (TTL value ).

    Since I discovered that the line voltage (from the building ) when converted to DC ( Mastech DC voltage supply ) doesn't give a clean signal ( contains spikes ).
    I decided to use a 12V battery for the purpose.

    I am using a LM7805 IC. Can some one please provide me a circuit Idea as to how I can use this voltage regulator IC to build a circuit that gives +5v and how to avoid spikes ( get a clean signal ).
  2. russ_hensel

    Distinguished Member

    Jan 11, 2009
    Refer to its data sheet and google, pretty basic, you should have no trouble. You could also use the power supply as the input to the regulator, power out should be clean.
  3. zero_coke

    Active Member

    Apr 22, 2009
    Look at its datasheet and it has example applications section with schematics. Use one of those.
  4. spinnaker

    AAC Fanatic!

    Oct 29, 2009
    The 7805 is going to drop a lot of current with a 12V battery. You are going to waste most of your energy in heat and will drain your battery in no time. You should consider a switching regulator instead.

    The LM2675 from TI is very easy to use, just slightly more difficult than the 7805.

    The 34063 is a very common switching regulator. Older and less efficient than the LM2675 but very common. You can find one in those usb chargers that you find at the discount store. You could simply hack one of those.

    The 34063 is very flexible. You can step up or step down pretty much between any voltages. You can also change polarity.
    Last edited: Mar 22, 2013
  5. crutschow


    Mar 14, 2008
    How much 5 V current do you need?
  6. bountyhunter

    Well-Known Member

    Sep 7, 2009
    use an L-C filter