1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Electronics Simple voltage converter, how?

Discussion in 'Modding' started by Twellmann, 8 May 2006.

  1. Twellmann

    Twellmann Carnivorous Homunculus

    Joined:
    5 Jan 2004
    Posts:
    168
    Likes Received:
    6
    I need a simple voltage converter circuit :D

    I need 1,2V out and I wan't to be able to hook it up to various batteries, 7,2 9 or 12 volts or the likes

    I'm not quite sure as to how much current I need out of this thing, but no more then 1 amp

    It will drive the glow plug on a Nitro RC car

    In short:

    2-20 Volts in

    1,2-1,3 volt out max 1000mA

    edit:

    I guess this could be used at Farnell #9493301
     
    Last edited: 8 May 2006
  2. Confused Fishcake

    Confused Fishcake New Member

    Joined:
    25 Sep 2005
    Posts:
    698
    Likes Received:
    1
    Just get any fixed 1.2V voltage regulator, or use one like the one at farnell. Basically, any electronic company will sell something suitable, best if you can get a fixed 1.2V one. (Less parts)
     
  3. Starman97

    Starman97 New Member

    Joined:
    17 Sep 2003
    Posts:
    54
    Likes Received:
    0
    You can use a linear regulator like the LM317T (see digikey)
    The only trick is that if you pull 1 Amp from the output,
    that means 1 Amp is pulled from the input power source.
    That's all fine, but 1 Amp at 1.2V is only 1.2 Watts,
    what happens to the (20v - 1.2V) * 1Amp = 18.8W ?
    It gets turned into heat in the regulator. So you're going to need a
    BIG heatsink if you run this for more than a minute or two.
    Even if you only run it for a few seconds, you still need a heatsink,
    that TO-220 package will burn out with 18W.

    Your other option is a switching power supply. These are more expensive,
    but far more efficient. The problem is, finding one that fits your
    requirements of 3-20V in and 1.2V @1A out. Not a big problem if
    you can design your own. Look up National Semiconductor's Simple Switch
    line, they have a web-based circuit designer. They also sell SimpleSwitch
    kits, not cheap, but they do what you want.
     
  4. Wolfe

    Wolfe New Member

    Joined:
    7 Sep 2003
    Posts:
    776
    Likes Received:
    1
    The lm317 only goes down to 1.5 v
     
  5. cpemma

    cpemma Ecky thump

    Joined:
    27 Nov 2001
    Posts:
    12,328
    Likes Received:
    55
    Nominally 1.25V (+/-0.05V) which shouldn't hurt, and you could treat it as a fixed voltage regulator, no need for any resistors. Just connect the adjust pin straight to negative. Presumably this is only on for a short time, so whilst you need a decent heatsink it doesn't need to be enormous.
     

Share This Page