1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Voltage drop question

  1. Jul 24, 2015 #1

    i have a 24 volt buss in a machine and i need to connect an lvdt sensor to the plc i show a 1.5k resistor that is .5 watts on the lvdt. what need to find out is the voltage drop at the resistor. i formula asks for I but I but i don't have I so what might the votage drop be. answer or formula will help thanks

    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
    Last edited by a moderator: Jul 24, 2015
  2. jcsd
  3. Jul 24, 2015 #2


    User Avatar

    Staff: Mentor

    Can you post the schematic of the system and the datasheet for the sensor?
  4. Jul 24, 2015 #3
    i don't have a diagram nor any data for the sensor at this time but if you draw the left side of the ladder at 24 volt + and then put the .5 watt resistor on a rung then attache the 24 + power input sensor wire to that. then the sensor has the ground and the wiper on that lvdt is the output. i gather the sensor is a Imax < 1ua that is what i see on it.

    so what i'm trying to figure out is the voltage drop accross that resistor i used the ohm's law but i asks for I and i don't have I i have 24 volt + and i have 1.5k ohm's and i have .5 watts for the resistor.

    i'm thinking the sensor is changing current to the output to the plc and not the volts but i'm not sure. so that is why i asked the question all the numbers i plug into this show a voltage that doesn't make sense to me. maybe someone here can help figure this one out. thanks
  5. Jul 24, 2015 #4


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    If you want to know the voltage drop across the resistor, put a volt meter across it and measure the voltage drop directly.
  6. Jul 30, 2015 #5


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    I cannot understand that description. Can I suggest you make a drawing and post it here.

    Are you trying to use a 1.5K potentiometer as a potential divider to provide power for the sensor?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted

Similar Threads - Voltage drop question Date
Voltage Drop PTC Thermistor Nov 23, 2017
Voltage drop question - need check/advice Oct 19, 2014