voltage to current converter

Discussion in 'General Electronics Chat' started by Jim_2.0, May 14, 2006.

  1. Jim_2.0

    Thread Starter Well-Known Member

    May 14, 2006
    51
    0
    Hi Guys

    wondering if anyone can help me with a basic circuit. I need a reliable and accurate voltage to current converter, to take in 0-5V and output 4-20mA. I have tried the traditional howland circuits, but having to many issue, im not too great on the electronics side of things. Can anyone suggest a suitable circuit, or any resources? Any help much appreciated.
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,163
    1,797
    Try the following link to Analog Devices. You may have to use a gain stage to convert 0-5 into one of its input ranges but this should get you started

    Analog Devices Current Loop Transmitter
     
  3. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Greetings Jim_2.0,

    In case you are interested in a typical technique for voltage to current conversion, you may benefit from reading the information that is available in the tutorials on this website.

    For your convenience I have included a link to the specific section on this topic. It may also help you to better understand the technique by reviewing some of the material on operational amplifiers since these devices are frequently used as the basis for voltage to current conversion.

    Basic V-to-I description

    I'm sure one of our members can assist you with any followup questions you may have.

    hgmjr
     
  4. n9352527

    AAC Fanatic!

    Oct 14, 2005
    1,198
    4
    hgmjr, do you think the current designator arrows on that page should point the other way around or not? Or am I having one of those days?
     
  5. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    Depends on whether one defines current as "a flow of moving electrons" or as "a flow of positive test charge carrier from source anode to source cathode."
     
  6. n9352527

    AAC Fanatic!

    Oct 14, 2005
    1,198
    4
    Yeah true. I guess the site uses electron flow notation throughout.
     
  7. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    n9352527,

    Well spotted. Like you, I have always considered current to move through a load (in this case Rload) from the positive most terminal (in this case the opamp's output) to the more negative terminal (in this case the opamp's minus input). Thingmaker3 has stated the two conventions that are out there. The main thing is to pick one convention and use it consistently.

    hgmjr
     
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