What is Wheatstone bridge: Definition and 81 Discussions

A Wheatstone bridge is an electrical circuit used to measure an unknown electrical resistance by balancing two legs of a bridge circuit, one leg of which includes the unknown component. The primary benefit of the circuit is its ability to provide extremely accurate measurements (in contrast with something like a simple voltage divider). Its operation is similar to the original potentiometer.
The Wheatstone bridge was invented by Samuel Hunter Christie (sometimes spelled "Christy") in 1833 and improved and popularized by Sir Charles Wheatstone in 1843. One of the Wheatstone bridge's initial uses was for soils analysis and comparison.

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  1. M

    NEED HELP Wheatstone bridge and DC series/parallel Please look

    NEED HELP ASAP! Wheatstone bridge and DC series/parallel ! Please look! I have three problems I need help solving. Problem #1: Fine the value R1 in the figure if R2 = 30ohm, I = 0.5A and V = 10V My try was: Rp = R1 + R2 , 20 = R1 + 30 , R1 = -10? ** please look for...
  2. E

    Weird Oscillation in wheatstone bridge circuit

    I have this weird oscillation coming from my circuit. its a wheatstone bridge with a single strain gage. I am using The PST 4130 from Omega Engineering to supply +10vdc. When I first turn it on the signal is pretty clean, but after a while, it turns into this...
  3. C

    Wheatstone Bridge - Max power delivered

    Homework Statement The Attempt at a Solution I was able to find the net resistance as its a balanced wheat stone bridge ... But how to find R for max power delivered?
  4. U

    Why Does a Wheatstone Bridge Offer Higher Accuracy in Resistance Measurements?

    Homework Statement 1. Why is the Wheatstone bridge measurement capable of so much greater accuracy than the measurement or resistance with voltmeters and ammeters, using R = V/I? and 2. R in this experiment is a resistance box and so is accurate to the nearest ohm. Is this uncertainty in R...
  5. N

    Wheatstone bridge offset-nulling circuit

    Hi all, I’m making a simple cantilever beam measurement system using 2 strain gages (120Ω). The two gages make up one leg of my Wheatstone bridge; the other leg will be made up using 120Ω resistors. Because of tolerances etc I will need to null the system before I add any weight to the end...
  6. R

    Understanding Wheatstone Bridge: Benefits and Simplified Explanation

    Why would one use a bridge measurement circuit instead of a wheatsone bridge (I know for increase accuracy) This website I found explains it (I think) but its far to complex: http://www.sensorland.com/HowPage002.html Can someone please explain it simply
  7. James889

    Get Expert Help with Wheatstone Bridge Circuit Analysis - 15mV Voltage Given

    Hi, I have this circuit: [PLAIN]http://img813.imageshack.us/img813/1189/wheatstone.png All resistors are 1K except Rx which is unknown. The voltage across the terminals are given to be 15mV. Im assuming i have to write a KCL equation but I am not sure how. Any hints?
  8. M

    Does a 10% Change in Power Supply Voltage Affect a Balanced Wheatstone Bridge?

    Homework Statement Suppose that in the course of a measurement the bridge is balanced and then the power supply voltage changes by 10%, what will happen to the balance of the bridge? Explain. Homework Equations No equations. The Attempt at a Solution When I think it out...
  9. Saladsamurai

    Wheatstone Bridge Strain Gauge Question

    Homework Statement I recently did a bending lab with a WB Strain Gauge in a bunch of different configurations. One measurement in particular is bothering me. Referring to the figure below, there are four strain gauges, Yellow, Orange, Black and Red mounted to a cantilevered beam with an...
  10. V

    Minimum microstrains that a wheatstone bridge or strain gauges will pick up?

    I'm wanting to measure the torque output of a cyclist by measuring the shear force induced in the crank arms. I've done some calculations for the minimum amount of strain that I'll want to pick up and it is around 6e-6 m/m. I'll be using a full wheatstone bridge with a constant voltage...
  11. S

    What exactly is a wheatstone bridge? What are its uses?

    I would like to know what is a wheatstone bridge? I read that it is an arrangement of resistors but i am not understanding how it works and the whole concept. Any help would be appreciated. Thank You.
  12. T

    Wheatstone bridge to measure high resistances?

    Can a wheatstone bridge be used to measure very high resitances with good accuracy? If not what problems interfere?
  13. C

    Engineering Converting Wheatstone Bridge: Possible or Not?

    In the attachment below, I have a picture of both an original wheatstone bridge and my attempt at converting it to a more familiar looking circuit. Is what I did correct/even possible? I just want to get a better understanding of these types of circuits. Thank you for your time!
  14. O

    A beginning RC circuit that resembles a wheatstone bridge

    Everybody knows what a wheatstone bridge looks like. R1 and R2 are on top and R3 and R4 are on bottom and R5 is in the middle of the angled box shape. let's replace R1 and R2 with 2 different capacitors. Let's also replace R5 with a switch. How would you figure out the potential...
  15. O

    Calculating Wheatstone Bridge with R1=600, R2=R3=R4=400, V Supply=10V

    if r1 has value of 600 and r2=r3=r4=400 ohms. supply voltage is 10v. im getting the wrong answer and do not know how. im using [(R4R2 - R3R1) / (R1+R4)(R2+R3)] * VS i get an answer of [160000 - 240000 / (1000)(800)] * 10 = [-80000 / 80000] * 10 = -1ohm but this is the incorrect answer...
  16. C

    About Wheatstone Bridge Method

    I need your help to finish my homework.I have only two questions 1-If a diameter of a wire is doubled,what happens to its electicial resistivity? 2-Why is different the resistivity of materials? Thanks
  17. T

    Electrochemistry (batteries), Wheatstone bridge question.

    Hi, I am using a Wheatstone bridge to measure very low resistances (around 0,2ohms) and my measurements are changing from day to day. If I take the resistance measurement of the same resistor several times, I notice that each measurement will be lower than the next. But the next day, the...
  18. G

    Wheatstone bridge in Linear Algebra

    Homework Statement I remember in physics class that we saw this set up.The ratio of r1/r4=r2/r3 is the same. There is no use for the current to head through R5 if it's the same energy on both sides. Now in linear I have no idea how to use this. Homework Equations ? The Attempt at a...
  19. S

    How is the Wheatstone Bridge equation affected when VG is not zero?

    I need help! WHEATSTONE! Homework Statement http://en.wikipedia.org/wiki/Wheatstone_bridge My pic. is almost same as this one, but R2 on the pic. is Rx at mine, Rx at the pic is R4 at mine. Pleas draw it up and help me: Homework Equations VE(voltage at left) is 9 V. VG(voltage in...
  20. K

    Solving a Wheatstone Bridge with 5 Resistors

    Homework Statement A Wheatstone Bridge with 5 resistors http://img529.imageshack.us/my.php?image=physicsproblemmo7.png Homework Equations Use Kirchoff's Law The Attempt at a Solution I know that I have to use Kirchoff's laws to find the current at each junction and then at the...
  21. G

    Question about using a wheatstone bridge to measure changes in resistance

    Hi I need to measure the small changes in resistance of a strain gauge. I have read that a wheatstone bridge circuit is used to do this.. but I don't understand why I can't just use a milliammeter to measure the change in current through the strain gauge and then use R=V/I to find the new...
  22. I

    Wheatstone bridge/ strain gauge question

    Need to do an experiment where I masure the strain of wood due to changes in temperature. I believe I need to use 2 strain gauges, one to measure the strain and the other to act as a dummy to cancel out any affects that heating will have on the strain gauge. I also know that a wheatstone bridge...
  23. H

    Why Did Our Geophysical Group Use a L&N Bridge Instead of a Slide-Wire Bridge?

    My teacher gave us this problem to work on: Homework Statement Some years ago I worked with a geophysical group that was looking for water in the Yuma Arizona area. Boy what it hot! Because of the high temperatures in the summer, water was badly needed in large amounts to irrigate crops...
  24. M

    Wheatstone Bridge: AC Source Effects on Balancing Condition

    Homework Statement Will the balancing condition get modified in Wheatstone bridge if AC source is used instead of a battery ? Homework Equations The Attempt at a Solution
  25. M

    Finding Vg with Wheatstone Bridge: R1=40, R2=70, R3=50, R4=20

    1. I am having trouble finding the Vg for a problem involving a Wheatstone Bridge circuit. If I am labeling the problem correctly, R1=40, R2=70.0 R3=50.0 and R4=20.0. Voltage - in = 20.0V I am using the formula: ((R1*R3) - (R2*R4) *V-in) / (R1 + R2) * (R4+R3) to find Vg between points B...
  26. I

    Solve Wheatstone Bridge: Homework Statement & Equations

    Homework Statement I think I got part A. I'm complete lost with b -d and help would be greatHomework Equations https://www.physicsforums.com/attachment.php?attachmentid=10986&d=1190644998 The Attempt at a Solution It think part d is ∆V = [(∆R1 - ∆R2 + ∆R3 –∆R4 ) / 4R ] * Vo But I'm not sure...
  27. M

    Effective reisistance of an unbalanced wheatstone bridge.

    Homework Statement I have an exam and therefore quick help is requested. I need a simple way to find out the resistance of an unbalanced wheatstone bridge. Suppos R1=2 ohm, R2=1 ohm, R3=4 ohm, R4=4 ohm and the connecting bridge's R5=10 ohm. Here, R1/R2 is not equal to R3/R4. Then How to...
  28. P

    Establish wheatstone bridge priciple by using kircchof's law

    How i can Establish wheatstone bridge principle by using kircchof's law?please tell me in details or send pdf or .doc files to:pavelavw@yahoo.com
  29. C

    Engineering Theveninizing a Wheatstone Bridge Circuit

    I'm working on a problem that has me confused. Perhaps someone might know of a resource with examples of different Wheatstone bridge circuits both balanced and unbalanced that use Thevenin's Theorem by eliminating different resistors from the bridge. The bridge I'm working with has one DC...
  30. N

    Understanding Wheatstone Bridge Circuit: How to Solve for Unknown Voltages

    How do i solve this? I wasn't given any examples at all. But I've tried to do this. Iab + Iad = Ibc + Idc <--------- they have to or else Kirchoff's law violated. so Vab = Vad but I'm not sure if Vbc = Vdc? i'll continue assuming Vbc = Vdc Vab/40 + Vad/20 = Vbc/70 + Vdc/50...
  31. W

    What is the key to solving an unbalanced Wheatstone bridge with a current value?

    We have been doing a lot of work with wheatstone bridges in class lately and our teacher gave us a problem to try and I'm totally lost. The diagram that we were given has a 40 volt battery hooked to a wheatstone bridge circuit. The positive power flows into two resistors, one is 9 kiloohms and...
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