Voltage Drop Question: Calculate w/o I

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Discussion Overview

The discussion revolves around calculating the voltage drop across a 1.5k ohm resistor connected to a 24 volt bus in a machine, specifically in relation to an LVDT sensor interfacing with a PLC. Participants explore the implications of not having the current (I) value needed for the calculation and seek clarification on the setup.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant seeks to find the voltage drop across a 1.5k ohm resistor without knowing the current (I), expressing confusion over the calculations.
  • Another participant requests a schematic and datasheet for the sensor to better understand the setup.
  • A participant describes the configuration of the circuit, mentioning that the sensor has a maximum current of less than 1 microampere, but expresses uncertainty about the relationship between current and voltage in this context.
  • One suggestion is made to measure the voltage drop directly using a voltmeter across the resistor.
  • Another participant struggles to understand the circuit description and suggests creating a drawing to clarify the setup, questioning whether the resistor is being used as a potential divider for the sensor.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the circuit configuration or the method for calculating the voltage drop, indicating that multiple views and uncertainties remain regarding the setup and calculations.

Contextual Notes

Participants note the absence of a circuit diagram and specific data for the sensor, which may limit the ability to accurately assess the situation and perform calculations.

corvairbob
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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. Homework Statement

Homework Equations

The Attempt at a Solution

 
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corvairbob said:
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. Homework Statement

Homework Equations

The Attempt at a Solution


Can you post the schematic of the system and the datasheet for the sensor?
 
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 across 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
 
corvairbob said:
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 across 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
If you want to know the voltage drop across the resistor, put a volt meter across it and measure the voltage drop directly.
 
corvairbob said:
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.

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?
 

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