Talk:Wheatstone bridge

message: The concept of a balanced bridge is central to many practical uses of bridges. Someone needs to explain this. Is this a good place? As a measurement tool, we adjust the bridge to balance, or null, to establish the unknown value by comparison with the known arm. However the balance concept is fundamental to many applications of bridges that are not measurement related, and is a key idea used by circuit designers. It allows the currents flowing across the horizontal paths to be independent of the voltage imposed on the vertical paths.
--AJim (talk) 20:26, 29 October 2008 (UTC)
thread_title: need to discuss the concept of balance

message: Can't we tell how it was used?  This is in the bowels of the technology and does a great disservice to the fact that it was the first piece of network management gear.  - carl ford cford@imhocorp.com  —Preceding unsigned comment added by 67.80.28.24 (talk) 11:06, 28 October 2008 (UTC)
replies: text: Updated with the correct inventor -- DrBob 18:54 30 May 2003 (UTC)
Should we add the balance conditions for the wheatstone bridge? mickpc
I added the voltage divider equation used to detect resistance changes.  Should we start a related discuss on RTD's?  Three vs 4 wire?--Kdcarver 21:32, 11 October 2005 (UTC)

text: It seem that the formula to calculate the Equivalent Resistance RE has a little error
(R1*R2)(R3*R4) should be replaced by (R1+R2)(R3+R4). Please verify my suggestion. Tks.
what about the emeter in referance to scientologys use of this type device?
I kindly request a brief discussion of how AC measurements are made with a Wheatstone... and/or how to measure inductance and capacitance (or a link to said information).  If anyone is familiar with that, thanks in advance.  Catapultsam 11:15, 15 April 2007 (UTC)
thread_title: Misc. comments

message: In the article, they say that the first set of equations are for B and D.  I believe the author meant B and C as current I1 does not feed into D.—The preceding unsigned comment was added by ZaydHammoudeh (talk • contribs) 22:09, May 31, 2006 (UTC).
Current article is wrong. Someone changed the image without checking definitions in the article.Orz.(Sorry, I don't have enough time to correct it now.)—The preceding unsigned comment was added by 155.230.100.86 (talk • contribs) 04:11, June 7, 2006 (UTC).
:I restored the original diagram and adjusted some of the changes that had been made since it was replaced on May 22. The newer diagram, while perhaps nicer-looking, uses different numbering of the resistors and junctions. This change in numbering left the mathematical derivation incorrect. Several editors had made changes to individual sentences where they noted a discrepancy with the diagram, but this was not sufficient to fix the problem. I have reverted those changes, so the article should now be in accord with the diagram. 
:If the consensus is that the other diagram is better, someone needs to go over the article carefully and rework the derivation so that it is in accord with the new diagram. Alternatively, someone could relabel the new diagram so it matches the old one's numbering.--Srleffler 17:18, 23 August 2006 (UTC)
thread_title: Diagram

message: It's a good start, but needs more :)  For instance, the circuit on the page is specifically a quarter-bridge set up.  A good site to refer to for more info is  though the focus there is more on strain gauges.  Try  too.  Happy editing :)  —Preceding unsigned comment added by Cirmae (talk • contribs) 23:53, 11 May 2009 (UTC)
thread_title:  please elaborate 

message: Replacing V_g with R5 and Rx with R4, and solving in terms of conductance (G1=1/R1, etc) I came up with this: 
                    (G1*G4-G2*G3)
 V5 = Gs *          ------------- 
           (G1+G2)(G3+G4) + G5(G1+G2+G3+G4) 
This seems right, but then I work a problem like this once every five years or so.  The sign of V5 is a matter of convention.  My diagram was D-B but I think the equations in this article use B-D.  I would have liked to find this in the article rather than work it myself, but then this is no longer a balanced bridge so perhaps it doesn't belong. — MaxEnt 11:30, 8 July 2013 (UTC)
thread_title:  Equation for Rg 

message: I'm not sure about the claim at the beginning that Wheatstone bridge is more accurate than a voltage divider at measuring resistances, well at least for the unbalanced bridge which is the only thing talked about in the citation #1 that follows its. Furthermore, this citation actually doesn't compare the bridge with a voltage divider, just it just compares it with using a voltmeter & current meter method instead so this is not a great source for this claim.
From my current understanding, the unbalanced Wheatstone bridge is simply two voltage dividers (since the middle is open circuited). Thus, I would expect the accuracy to be the same; the output voltage is sensitive to changes in the supply voltage or temperature coefficient differences between the reference and unknown resistors. It seems like the only advantage of the Wheatstone bridge in this circumstance is that can add a DC offset (approximately) to the output measurement to make the output more convient in circumstances were the change is small relative to the absolute value. For example, if you have a PRT with a 1000 ohm resistance at 0 C and 1100 at 25 C, you could set the resistor appropriately such that you get 0 V at 0 C.
I don't see where the accruacy improvement comes from for the unbalanced bridge (I agree the balanced bridge is more accurate). Does anyone agree/disagree?
Nate266 (talk) 01:09, 19 August 2021 (UTC)
replies: text: I agree that to make the article clearer we need a current application for the circuit and to be fair I do not know of any. 2001:8F8:1761:8F2D:FC48:CC11:82A7:9741 (talk) 03:28, 5 May 2022 (UTC)
thread_title:  Accuracy of Unbalanced Bridges