What is Bridge: Definition and 481 Discussions

A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually something that is otherwise difficult or impossible to cross. There are many different designs of bridges, each serving a particular purpose and applicable to different situations. Designs of bridges vary depending on factors such as: the function of the bridge, the nature of the terrain where the bridge is constructed and anchored, and the material used to make it and the funds available to build it.
The earliest bridges were likely made with fallen trees and stepping stones. The Neolithic people built boardwalk bridges across marshland. The Arkadiko Bridge (dating from the 13th century BC, in the Peloponnese) is one of the oldest arch bridges still in existence and use.

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  1. S

    LaTeX Discover the Use of LaTex for Bridge and Chess Online Discussions

    I'm curious whether LaTex is commonly used to display online discussions of bridge and chess? (Yes, if I investigated online Bridge or chess forums, I'd find the answer. However I hope someone who knows will save me the trouble.) Just a casual search for "LaTex for bridge deals" shows that...
  2. C

    Calculating Copper Wire Gauge for Resistance Thermometer Bridge Circuit

    a. The resistance thermometer bridge circuit shown in FIGURE 1 has a designed maximum temperature of 200°C, ignoring the effects of connecting wire resistance. If the connecting loop is 250 m determine the smallest gauge (swg) of copper wire which must be used if the indicated maximum...
  3. P

    I Measuring Low Resistance: Why Meter Bridge is the Preferred Choice

    Why meter bridge is chosen over post office box to measure low resistance?
  4. HelloCthulhu

    How does an electric field create velocity in a water bridge?

    I've been researching water bridges and electrowetting to learn the effects of electric fields on water molecules but something continues to confuse me: if polar molecules can only rotate in an electric field, how is the water moving? Anyone familiar with this phenomenon? Any help is greatly...
  5. wnvl2

    Salt bridge and electical field

    Is it correct that a salt bridge in a Galvanic cell makes that there is no electrical field between the solutions of the two hallf cells? Does that mean that the electrical potential (I do not write electrochemical potential) between both solutions is zero in an ideal world? Is it also possible...
  6. WMDhamnekar

    MHB Sample space and bridge game

    Bridge : For k= 1,2,3 ,4 let $N_k$ be the event that North has at least k aces. Let $S_k, E_k, W_k$ be be the analogous events for South, East, West. Discuss the number x of aces in West's possession in the events a)$W_1', $ b) $N_2S_2,$ c) $N_1'S_1'E_1'$ d) $W_2- W_3$ e)$N_1S_1E_1W_1$ f)...
  7. Shreya

    Voltage Null Points of a Mechanical Meter Bridge

    My reasoning is that the wire has a resistance/unit length. The resistance of AD must equal that of AB for D to be called a null point. If we move jockey to the left, the resistance of AD decreases, thereby decreasing the potential drop across it. This means that the V of D is more than that of...
  8. F

    Wheatstone bridge and conditions for current to flow between 2 points

    Hello, I was reflecting on the functioning of a balanced Wheatstone bridge circuit: Point C and D are at the same electric potential V (zero potential difference). Even if they are connected by an ideal zero resistance wire, current will not split at either node C or D to flow through that...
  9. S

    Modification of Wheatstone Bridge

    I want to ask what the total resistance of the circuit will be if R2 is removed and being replaced with ideal wire. I think R1 and R3 will be parallel → let this be R6 R6 will be series with R4 → let this be R7 Then R7 will be parallel to R5 Is that correct? Thanks
  10. S

    How to do the calculations for a Wheatstone Bridge

    I know at balanced condition, the current flowing through galvanometer = 0 and R1 . Rx = R2 . R3 What I want to ask is how to analyze the circuit until we can conclude the current will be zero. I have learned about Kirchhoff's 1st and 2nd law and also about potential divider. I am guessing...
  11. D

    Endless bridge around the equator and gravity

    Hi, I’ve got a question. it seems that engineers, structural mainly, don’t seem to understand how gravity works regarding an endless stationary (steel) ring/bridge around the equator. Many if not all have said that such a ring would be modeled as two half circles pushing into each other. So the...
  12. PhysicsTest

    Static power bridge motor drive circuit

    I am referring to the application note from TI, the below is the power bridge circuit. The truth table is as below a. I try the first values of A=0, B=0, C=0 the circuit would then become like this according to me It is open above point O, then how the voltage of ##\frac{-V_{DC}} 2## will be...
  13. Dman0500

    Dynamic Equilibrium -- Acceleration of a rock thrown from a bridge

    I know the acceleration of the rock is equal to g, but why. If we neglect air resistance, what is actually making the rock fall? Wouldn't it be that g overcomes the acceleration of the y plane at some point so the rock starts coming down or in this case accelerate more by throwing below 0 degrees?
  14. handyman123

    Not able to get the desired output frequency using a Wein Bridge Oscillator

    Can anyone help me find what is wrong in this circuit? given, slew rate of the op amp is 400V/us and max output current for opamp is 40mA but the opamp is lm741.
  15. Entertainment Unit

    B The Probability that N and E bridge hands have the same number of spades?

    My answer is as follows: Let ##S## be the set of all outcomes of dealing four labelled 13-card hands from a standard 52-card deck. Let ##A## be event "N and E have exactly the same number of spades." Let ##A_i## be event "N and E have exactly ##i## spades each." Note that when ##i > 6##...
  16. HelloCthulhu

    Arcing during water bridge, which dielectric breaks down first?

    I've been interested in the effects of electric fields on water for a while and came across this impressive demonstration of the water bridge experiment: The thing that fascinates me the most is how much the electricity arcs out of the water. For example at timestamp 8:43 the arc clearly goes...
  17. wengler

    B Einstein-Rosen Bridge: Exploring Conditions, Detection & Stability

    Under what conduction's can a Einstein–Rosen bridge form? Could they be detected ? How stable would a Einstein–Rosen bridge be?
  18. K

    Discharging this capacitor in an RC bridge circuit

    The voltage source in the circuit below has been switched on for a long time when the switch S switches off. How long will it take before the current coming out of the capacitor has become less than 1 mA? My attempt: I am far from sure that my solution is correct. This is because i...
  19. bagasme

    Wheatstone Bridge: Substitution Resistance Formula Derivation?

    Hello, In high school, I had been taught about finding substitution resistance from Wheatstone bridge. The formula: a. If the cross product of ##R1## and ##R3## is same as ##R2## and ##R4##, the galvanometer in the middle (##R_5##) can be omitted and use series-parallel principle to solve for...
  20. Boltzman Oscillation

    Engineering How should an H bridge circuit be analyzed?

    If I am given an H bridge circuit such as that below: How would I go on analyzing it? I would personally replace all of the transistors by their circuit models but then what would I do with the motor? Do I replace the motor with it's load resistance or is there more to it? I guess motors are...
  21. Lietenacious

    Best truss bridge design for this school project?

    Summary:: In my course, we have to design a truss bridge (made out of balsa wood sticks) that can withstand the most weight compared to its mass. It’s our final, so very important haha. One of the rules is we can’t stack the wood right on top of each other to support it (just preventing us from...
  22. U

    Very basic circuit question about a Wheatstone Bridge

    I tried to solve by making 4 ohm and 8 ohm, which I believe are parallel as one effective resistance, and making 6 and 12 ohms which I believe are parallel as one effective resistance, and diving the total of the two effective resistance by the total voltage, but by doing so, I can only find...
  23. Shashwat02

    B Normal force of a body over a circular bridge

    I am not able to understand why normal force on top in a vertical circular motion the least. Also please help me with normal force of a body over convex and concave bridges. Why do we get these equations: N=mg-mv2/r (convex bridge) N=mg+mv2/r (concave bridge)
  24. D

    Unable to get a Wien bridge oscillator to work

    I am unable to get the wien bridge Oscillator I built to work. This same Circuit has worked several times. Sometimes the same circuit works. Sometimes the same circuit does not work. When it works I can get A led to blink and can build a frequency divider. How do I troubleshoot this circuit...
  25. Janus

    Have you seen the 3D render of the iconic Enterprise bridge in Blender?

    A couple of weeks ago another poster (@ElliotSmith) posted a 3D model he did of a reactor control room in Blender. This inspired me to do a model of a different kind or "control room", the bridge of the starship Enterprise. The model is not fully complete as many of the areas not shown in...
  26. khalil977

    Do I Need Freewheel Diodes for My H Bridge Mosfet Inverter Circuit?

    i am designing H bridbe mosfet inverter with gate driver HCPL3120 i need help in circuit
  27. PaxFinnica96

    Calculating the Gauge of a Copper Wire for a Thermometer Bridge Circuit

    Hi All, Really struggling to get my head around what I'm doing wrong - every time my answer of wire diameter comes out too small for what's included in the table of SWG. I must be doing something wrong somewhere - my attempt is below. Any help is very much appreciated.
  28. T

    PCB design and schematic for a half bridge power amplifier

    Hi, I am making a half bridge power amplifier that operates at 24 V. The bridge has to supply around 3A current to an inductive load (10mH) The bridge will be controlled using 20kHz PWM from a microcontroller. I have put a ACS712 current sensor in the load path to give feedaback to the...
  29. D

    How do I tell if the Wien bridge oscillator I built works

    I built a wien bridge oscillator. But how do I tell if it works? I am very new to building circuits. I recently Starting making circuits on a breadboard. I have not taken any Electronics class. I am trying to learn how to do this.
  30. R

    Help with Wien Bridge Homework: Estimating Capacitance Values

    Homework Statement When testing the circuit of FIGURE 1 (a) it was found that the output shown in FIGURE 1 (b) was obtained when the input was connected to ground. explain why this was so and attempt an estimate of the capacitance values of C.Homework EquationsThe Attempt at a Solution...
  31. morrobay

    Opinions On This 50m Steel Span Bridge Without Supports

    The bridge sections in photo are being welded / bolted ? together on site. Is this going to be structurally strong enough for a pedestrian bridge ?
  32. DracoMalfoy

    A stone is thrown off a bridge....

    Homework Statement A stone is thrown off of a bridge that is 40m above the water. The stone lands 48m from the base of the bridge. The stone was thrown with an initial velocity of 15m at 30 degrees above the horizontal. What is the maximum height the stone reaches above the water? (ans:42.87m)...
  33. epenguin

    Bridge Collapse Genoa - Informed Engineering Perspectives

    The dramatic collapse of a bridge in Italy with many fatalities has been the big item of news all over Europe. https://www.theguardian.com/world/2018/aug/15/genoa-bridge-collapse-death-toll-italy-minister-calls-resignations and many other reports. I just wonder if the qualified people here...
  34. D

    DC Varley Bridge: Solving "Show That" Problems

    I am currently working on a module for the practical application of DC bridges. The particular problem I have at the minute involve "show that" questions. The first question is in 3 parts and reads as follows: - A Varley Bridge is connected to a faulty three core copper cable by two identical...
  35. K. Doc Holiday

    B Why Albert Einstein's Original Concept for a Black Hole?

    Einstein-Rosen Bridge Question: Why do we discard Albert's original concept for a black hole? I have one college astronomy textbook which doesn't even mention it. The only use seems to be in science fiction movies and books. Why? Is it possible that he actually got it right conceptually but...
  36. J

    Phase of a Wein Bridge Oscillator (AC Mains Harmonics Analyzer)

    Hello, I am working on a project to calculate harmonic distortion on a mains signal. The signal has already been stepped down so it oscillates between 0-5V at 50Hz. I looked into some old THD analyzers and it seemed they would generate a clean signal to mimic the fundamental deduct this from the...
  37. Deacon James

    Art Bridge Art -- Sundial Bridge at Reading, California

    Be sure the visit the Sundial Bridge at Redding, California.
  38. sweet springs

    B Exploring the Bridge Fall Paradox: A Look at Stress and Damage in Materials

    Bridge fall paradox Another thread urges me to think of stress in materials in TOR and let me make a "paradox" to think of it as follows. --------------- A train is running on a bridge over a wide river. Evil terrorists switch on the bombs set on legs of the bridge to crash whole the bridge...
  39. M

    MHB Bridge Game: Does Luck Matter?

    4 people are playing the Bridge Game, out of 4 players 1 player hasn't received a single Ace after third turn, does he have the right to complain that he doesn't have luck? To clarify some things - There are 32 cards (4 types), each of the four players get 8 cards for each turn. The problem is...
  40. I

    Wheatstone Bridge at Null position

    Homework Statement Consider the Wheatstone bridge as shown in the following figure, where ##e_0## is the Galvanometer reading. The condition for ##e_0 = 0 ## is called the null condition of the bridge. Using the Kirchhoff's rules, we can show that the condition is ## R_1R_4 = R_2 R_3##. Now I...
  41. Spinnor

    FIU pedestrian bridge install left it vulnerable to collapse, WTH

    "The pedestrian bridge in Miami that collapsed Thursday had only been put in place on Saturday under a process that allowed for installation of large sections — but that experts said left it vulnerable to collapse until it was complete." From...
  42. A

    Bridge Rectifiers: How Do They Work?

    Ok so I've been reading a book on electronics and I got to a section that talks about full-wave bridge rectifiers. This is the diagram the author gives: In this diagram he says the D2 and D4 diode are forward biased. But, doesn't the current flow through D2, goes through the resistor, and then...
  43. J

    Ripple frequency of three phase half bridge converter

    Homework Statement Homework Equations Three phase half controlled bridge rectifier can have 3 pules at output or 6 pulses depending on firing angle. The Attempt at a Solution Ripple frequency is m times the input frequency where m is number of pulses. It can be 3 or 6. So why have they...
  44. J

    Full Bridge Inverter: Got the answer by 1 method, but not by another

    Homework Statement Homework Equations Fourier and then V(output) = 4Vs/(n*3.14) * sin (nwt) where Vs is battery here it's 400V Current = V(output) / X(L). Here X is 2*3.14*100*0.2 The Attempt at a Solution I got V(output) = 4*400/3.14 = 509.55V This is fundamental Peak output voltage. So...
  45. J

    Average current in single phase bridge converter SCR

    << Mentor Note -- thread moved from the technical forums, so no Homework Template is shown >> I'm studying controlled rectifiers and for full wave bridge rectifiers the notes(that I'm studying from says) It says that the average load current is Id / 2 I don't understand how. Why should the 2...
  46. W

    Proof of Wheatstone bridge equation

    Homework Statement Prove the following equation: ## \Delta U=\frac {R_1R_4}{(R_1+R_4)^2}(\frac {\Delta R_1}{R_1}-\frac {\Delta R_2}{R_2}+\frac{\Delta R_3}{R_3}-\frac{\Delta R_4}{R_4})E## This is used in Wheatstone bridge Homework Equations [/B] U=RI The Attempt at a Solution This has...
  47. HelloCthulhu

    Floating Water Bridge and Dielectric Strength per Volume

    I recently watched a great video demonstrating the floating water bridge experiment: At around 34 sec, you can see an electrostatic discharge before the water bridge forms. I've read that this is due to the electrostatic breakdown of air between the two beakers.This made me curious about the...
  48. N

    Flow Over a Rotating Bridge CFD

    Hi everyone, This is my first post as I am a new member here. I am trying to simulate an opening of a bascule bridge and study the flow over it in Fluent. I simplified the problem by allowing the bridge to be represented by a flat plate and I used Reynold's Number scaling to scale my dimension...