What is Anode: Definition and 46 Discussions

An anode is an electrode through which the conventional current enters into a polarized electrical device. This contrasts with a cathode, an electrode through which conventional current leaves an electrical device. A common mnemonic is ACID, for "anode current into device". The direction of conventional current (the flow of positive charges) in a circuit is opposite to the direction of electron flow, so (negatively charged) electrons flow out the anode of a galvanic cell, into an outside or external circuit connected to the cell. In both a galvanic cell and an electrolytic cell, the anode is the electrode at which the oxidation reaction occurs.
In an electrolytic cell, the anode is the wire or plate having excess positive charge. Consequently, anions will tend to move towards the anode where they can undergo oxidation.
Historically, the anode has also been known as the zincode.

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  1. hagopbul

    Question about battery -- Looking into the electrode effects on the battery

    Hello All : i had few suggestions about battery enhancement using some ideas which i had just abstract understanding not enough even to suggest discussion but i have this question why we dont fold the anode and the cathode into geometrical shape , wouldnt that increase the number of...
  2. I

    Why is perforated cathode used in the discovery of anode rays?

    I really tried to solve it a lot and the info that I gathered is : Electrons or protons can be ABSORBED by cathode or anode so there must be some hole in the electrode for the rays to pass. These electrons ionize the gas and those positive gas ions move towards cathode.
  3. R

    Anode rods and their effect on steel piping

    Water heaters have a sacrificial anode rod inside of them to protect the steel tank. These rods are usually made of magnesium or aluminum, and sometimes zinc. Please note that zinc anodes are made of a combination of aluminum and zinc, 1 proportion of zinc to 10 proportions of aluminum. I...
  4. Skyland

    Tungsten Battery Anode: Charge & Experiments

    Does anyone know if a tungsten-/copper+ saltwater battery have any significant charge if any? Willing to experiment myself, but don't want to waste money without asking first
  5. WMDhamnekar

    MHB Cathode & Anode: Explaining the Difference

    Hello, In cathode ray discharge tube,negative electrode is cathode and positive electrode is anode. But in case of direct current circuit, it is the positively charged terminal of a voltaic cell or storage battery that supplies current and anode is the negatively charged terminal of a voltaic...

    Rapidly Dissolving Anode - Seeking Advise To Puzzling Problem

    Hi everyone! I am seeking advise to a corrosion problem, I have a circulator design I am working on. This is a 40 to 115 degree closed loop “city water” circulator. The water reservoir is 304 stainless and has a115v-1500w immersion heater, threaded into the tank. There is an overtempt snap disc...
  7. S

    Anode designation in a lead acid cell

    Hi, I am trying to determine the conventional cathode and anode designations for lead acid cells. From what I have researched: Anode is where current flows in the device, or where electrons flow out of. In a secondary cell the designations for anode and cathode are based on the discharge...
  8. S

    Best anode materials for water-based hydrogen generator?

    I want also to build electrolysis based hydrogen generator or and water oxygenator/aerator. It's simple electrolysis device but requires special electrodes that are corrosion resistant or at least safe for human consumption. I seen that hydrogen bottles use platinum titanium electrodes. Platinum...
  9. Zahid Iftikhar

    Collimation of an Electron Beam by the Anode of a CRT

    Please help me in understanding the function of anode. As in image attached you see, once the electron beam is emitted from cathode and filtered by grid, it enters into the one or series of anodes. As anode is positively charged, so, to my understanding it has no electric field inside its hollow...
  10. A

    Why is the Anode of an LED Connected to Positive?

    So, I'm new to electronics and I started to build some circuits with LEDs. I read up on how LEDs work and how they consist of a doped semiconductor material etc. But when I actually went to wire the LED in, it said the anode should be connected to the positive terminal of the power source. I'm...
  11. A

    How Batteries Work: An Electrochemical Explanation

    So, I'm a little confused on how batteries work. I understand they convert chemical energy into electrical energy. I also understand that the battery consists of an anode and a cathode with an electolyte in the middle to force the electrons from the chemical reaction to have to follow the wires...
  12. T

    Why do water heaters need an anode?

    I've read about water heaters needing anodes, but I don't really understand why. The objective is that the anode should protect the tank by "attracting" corrosion, isn't that right? But aren't water heaters usually made of stainless steel anyway? Around here most water heaters don't have an...
  13. H

    Electric field generation between anode and cathode

    Hi I'm running an experiment where I want to see the electrical field generated when I energise a submerged anode (an array consisting of 4 x stainless steel tubes spaced equidistance apart) and cathode array (similar to the anode) upstream and downstream of the flowing water tank (glass sided...
  14. JulienB

    Force acting on anode by electron current

    Homework Statement Hi everybody! I'm unsure how to tackle the following problem, hopefully some of you can give me some hints on how to do so. :) How big is the force acting on an anode by an electron current of strength ##I=0.3##A if the electrons are accelerated with a voltage ##U=300##V...
  15. J

    Product at anode of the electrolysis of MgBr2

    1. Homework Statement Why is the product at anode Br2 for MgBr2? Instead of O2? Homework EquationsThe Attempt at a Solution [/B] The EΘ value for the oxidation of OH- is -0.40 V, And that of Br- is -1.07V And so, shouldn't oxidation of OH- be easier? And hence, O2 is formed at the anode?
  16. N

    How do I calculate the cell potential?

    < Mentor Note -- thread moved to HH from the technical chemistryforum, so no HH Template is shown > I was given this problem: A voltaic sell uses the reaction 4Fe3+ + H2 --> 2Fe2+ +2H+. Find the cell potential when [Fe3+]=1.50 M, PH2=.50 atm, and [Fe2+]=.00100 M and the pH of both anode and...
  17. AnkurGarg

    Electrochemical cell electrode potential difference

    In our textbook it is written that -voltmeter measures the electrode potential difference between 2 half cells (in an electrochemical cell) (electrode potential refers to the potential difference between electrode and its salt solution in which it is dipped) it should come-voltmeter measures...
  18. M

    How to test a 1.5 pound magnesium anode

    Hello my name is Mike Moore and I work for Copperhead Industries, LLC We are a tracer wire manufacture for the underground non-metallic pipe utility sector, natural gas, water, sewer and telecom. We use magnesium anodes for grounding out the far end of the tracer wire system which completes...
  19. J

    What is the anode net charge on a typical AAA battery?

    I mean on the actually anode, what is the usual net charge around? How many extra electrons to protons are there? The reason I ask is because I'm confused what causes the voltage, is it the higher charge density relative to the other plate?
  20. S

    Magnetic anode for copper cathode battery

    Hello everyone from the Physics Forums, I'm doing a school project and I'm looking for a potential anode alloy that is ferromagnetic which I could use with a copper cathode. I'm making a battery and I have to use copper as my cathode mainly because I have made the cathode cells structured...
  21. S

    Searching for best ferromagetic cathode for aluminum anode battery

    This is a list of ferromagnetic materials that I've found on Wikipedia's category ferromagnetic materials page. I was wondering which of these materials would make possibly great cathodes for aluminum anode in the application of creating an sulfuric solution based acid battery. The battery I...
  22. A

    Help with fundamentals for understanding voltage, current, anode

    Hi, I have never been good at understanding how electricity works, I would appreciate very much if someone could help me get a good picture on my questions, maybe with some visual/easy/logical examples/thoughts? Electrons have a charge, in a metal they are free to move around, a charge in...
  23. Warpspeed13

    Will the material in a cathode be carried to the anode?

    If I were to strike an arc between a copper cathode and a tungsten anode would copper be deposited on the anode? If so how could I calculate deposition rate? I know this works in electroplating but will it work through air or another gas?
  24. A

    What is the direction of the anode heel effect in a rotating anode x-ray tube?

    anode heel effect occurs in a direction parallel to the anode-cathode axis?
  25. J

    Where Should I Place Sacrificial Anodes for a Tank?

    I have been searching the internet and this forum for information on where to place anodes or how far away they should be spaced but have not had much luck. I am trying to design a sacrificial anode system for the inside of a tank. Does anyone have any info to help or send me in the right...
  26. S

    The need for electrolytes between cathode and anode in battery

    My question is simple: Why do batteries need electrolytes? Wouldn't the battery need the charge to flow only through the circuit in the device being powered? The point of the anode and cathode's separation is to preserve the potential difference, so why allow charge to flow through an electrolyte?
  27. ajayguhan

    Why less originated area act as anode in a metal ?

    Why less originated area act as anode in a metal ?
  28. C

    Electroplating, anode and cathode help.

    I'm just having trouble understanding, I get the gist of it though. This is what I know in a electrolytic cell (I may be wrong): The cathode is negative, anode is positive and the current travels from the cathode to anode right? So during electroplating, the anode is the electrode being...
  29. S

    Work function and energy of X ray photon emitted by anode

    Hi guys, I'm constantly bothered by one assumption in my textbook..it says that the photon emitted by the accelerating electron boiled off from the cathode colliding into the anode, has E=hf neglecting the work function, since its negligible. I'm curious whether it's E=hf plus or minus the work...
  30. T

    Anode erosion of a moisture probe

    I'm working on a project in which I'm using a basic moisture sensor that I've made by sliding an insulated wire inside of a copper tube in such a way that the insulated wire with it's insulation extends past the tube about 1/8". That is then poked into the ground. On the other end of the copper...
  31. S

    Electrolytic Reactions: Anode vs Cathode

    hey guys i have put this question to clarify some points on battery anode cathode reactions...let me describe this..if we consider the cell to be two electrodes with in between electrolyte .. at anode one has the situation: metal=metal ion+electron released i.e oxidation takes place..! so...
  32. Q

    Quick question about Electrochemistry anode and cathode

    Homework Statement Pb/Pb2+ and Ag/Ag+ Ni/Ni2+ and Zn/Zn2+ Which one is the anode and cathode? Toward which metal do the electrons flow? The Attempt at a Solution 2Ag2+ + Pb ⇔ 2Ag + Pb2+ Pb is anode and Ag is cathode e- go toward Ag. Zn + Ni2+ ⇔ Zn2+ + Ni Zn is...
  33. I

    Selecting Anode & Cathode for Cu2(SO4) & Fe(SO4) Flow Battery

    A graduate student is trying to develop a flow battery based on aqueous solutions of 1 M Cu2(SO4) and Fe(SO4) (recall that the sulfate is divalent, e.g. (SO4)-2 and assume complete solubility). Given a chart like this : CHART How would I know that I need to select Copper (I) and Iron (II)...
  34. J

    WHen x-rays hit the anode is it true that they become accelerated

    Hi people :) I got two questions concerning x-rays 1. WHen x-rays hit the anode is it true that they become accelerated and as a result of thsi accelereation emmits radiation incl. x-rays? 2. in an characterstic spectrum how is it then possible to determine the exact atom which emitted...
  35. sunrah

    Mean Current of Photomultiplier at anode

    Homework Statement A weak light source (wavelength 600 nm, mean power 66.2 pW) falls on a multiplier tube with a cascade of 8 dynodes. How large is the mean current at the anode with an amplification of 108 and a 50% quantum efficiency for the photoelectric effect. Homework Equations E_{kin} =...
  36. M

    PEM Fuel Cell: Hydrogen Ion Diffusion Through Anode?

    Hey everyone, I was just wondering, in a PEM fuel cell the Hydrogen ion diffusion through the membrane is an important step. But don't these ions need to diffuse through the anode as well to reach the membrane? Also, if this is the case and the anode is a metal like Pt, wouldn't the diffusion...
  37. T

    Understanding Anode Break Excitation in Neuroscience: A Comprehensive Guide

    Hey, Can someone point me in the direction (or just explain to me!) the idea of Anode Break excitation in neuroscience ? Thanks
  38. H

    Anode And Cathode Through Conductor

    Homework Statement A conductor is aligned with Earth's magnetic lines of force. The compass set above the conductor points in a line parallel to the conductor. A DC power supply is connected to form a closed circuit with the conductor. Explain how this information could be used to identify the...
  39. D

    Cryogen-cooled x-ray tube anode

    As heat build-up is a major limiting factor in x-ray tube design, why can't the anode be kept at a low base-line temp to reduce heating and limit the potential for structural damage to the target? Does operating the x-ray tube at relatively low temperatures, say zero celsius, affect x-ray...
  40. T

    Exploring the Benefits of a Rotary Anode in X-Ray Tubes

    I am planning to undertake the construction of an x-ray tube as a personal project with a friend of mine and I was wondering what are the advantages of a rotary anode? I'm having no trouble finding information on their construction, but have yet to run across the reasons for using one in the...
  41. P

    Understanding Voltaic Cells: The Role of Fe3+ in the Anode

    The problem I have is just a detail I want to clarify about the voltaic cell. A standard cell is a voltaic cell in which each half-cell contains all entities shown in the half-reaction equation at SATP conditions, with a concentration of 1.0 mol/L for the aqueous solution. Referring...
  42. M

    Plating Metal - Cathode or Anode?

    "Plating" Metal - Cathode or Anode? Homework Statement You want to plate out nickel from a nickel (II) nitrate solution onto a piece of metal inserted into the solution. Should you use copper or zinc or can you use either of these metals? Homework Equations Standard Reduction...
  43. R

    Lead Dioxide Anode: Why Not Use Lead Strip?

    I usually plate lead dioxide on carbon to form my anodes, however, I was wondering if anyone knew why one can't use a lead strip and let electrolysis oxidize the surface to lead dioxide? It is too simple for it not to be used already. But I did make a set of lead acid batteries by just using the...
  44. L

    [Electrochemisry] How to find the Cathode and Anode, and oxidation and reduction

    Homework Statement This is from a lab question, but i think i did it right, i would just like some confirmation. I had to make an electochmical cell for a lab, (actually mutiple ones) but it asks me to find the anode, cathode, and which chemical underwent oxidation and reduction. If you have...
  45. P

    Anode vs Cathode: Charges & Uses Explained

    anode vs cathode? Hello everyone :) I am having a problem understanding the difference between the anode and cathode in electrochemistry. What I know so far is that the anode is the electrode at which oxidation takes place (and hence donates electrons) and the cathode is the electrode at...