Faraday's term " electrode," literally " a way (650s) for electricity to travel along," might be well applied to designate the insulated conductor along which the electric messenger is despatched.
The smaller cylinder is generally the negative electrode on which the copper is deposited.
The particular details of the phenomena observed will be found described in the article Electric conduction (§ The main fact discovered by researches of Plucker, Hittorf and Crookes was that in a vacuum tube containing extremely rarefied air or other gas, a luminous discharge takes place from the negative electrode which proceeds in lines normal to the surface of the negative electrode and renders phosphorescent both the glass envelope and other objects placed in the vacuum tube when it falls upon them.
In batteries which use acids as the electrolyte, a film of hydrogen tends to be deposited on the copper or platinum electrode; but, to obtain a constant electromotive force, several means were soon devised of preventing the formation of the film.
Thus, as long as every ion of the solution is present in the layer of liquid next the electrode, the one which responds to the least electromotive force will alone be set free.
Again, Hittorf has shown that the effect of a cyanide round a copper electrode is to combine with the copper ions.
Ordinarily carbon is used as the electrode material, but when carbon comes in contact at high temperatures with any metal that is capable of forming a carbide a certain amount of combination between them is inevitable, and the carbon thus introduced impairs the mechanical properties of the ultimate metallic product.
When the sounding board was spoken to or subjected to sound-waves, the mechanical resistance of the loose electrode, due to its weight, or the spring, or both, served to vary the pressure at the contact, and this gave to the current a form corresponding to the sound-waves, and it was therefore capable of being used as a speaking-telephone transmitter.'
electrode inserted into his cortex.
When the ions are set free at the electrodes, they may unite with the substance of the electrode or with some constituent of the solution to form secondary products.
On the other hand, it is commonly thought that the single potentialdifferences at the surface of metals and electrolytes have been determined by methods based on the use of the capillary electrometer and on others depending on what is called a dropping electrode, that is, mercury dropping rapidly into an electrolyte and forming a cell with the mercury at rest in the bottom of the vessel.
When the two electrodes are ferro-magnetic, the direction of the current through the liquid is from the unmagnetized to the magnetized electrode, the latter being least attacked; with diamagnetic electrodes the reverse is the case.
When the furnace with this well-known regulating device was to be used, say, for the melting of metals or other conductors of electricity, the fragments of metal were placed in the crucible and the positive electrode was brought near them.
An ingot gradually builds up from the bottom of the crucible, the carbon electrode being raised from time to time automatically or by hand to suit the diminution of resistance due to the shortening of the arc by the rising ingot.
In the specification of the patent applied for on the list of July 1877 he showed a sketch of an instrument which consisted of a diaphragm, with a small platinum patch in the centre for an electrode, against which a hard point, made of plumbago powder cemented together with india-rubber and vulcanized, was pressed by a long spring, the pressure of the carbon against the platinum disk being adjusted by a straining screw near the base of the spring.
When the amount of this ion in the surface layer becomes too small to carry all the current across the junction, other ions must also be used, and either they or their secondary products will appear also at the electrode.
In aqueous solutions, for instance, a few hydrogen (H) and hydroxyl (OH) ions derived from the water are always present, and will be liberated if the other ions require a higher decomposition voltage and the current be kept so small that hydrogen and hydroxyl ions can be formed fast enough to carry all the current across the junction between solution and electrode.
When a current passes from an electrolyte to a metal, the electron must be detached from the atom it was accompanying and chemical action be manifested at the electrode.
Other methods are to place the metal and mercury together in dilute acid, to add mercury to the solution of a metallic salt, to place a metal in a solution of mercuric nitrate, or to electrolyse a metallic salt using mercury as the negative electrode.
Everything else concerning electrode potentials is simply an attempt to attach some numbers to these differing positions of equilibrium.
Very little additional capacitance is added by the additional electrode and the restore function is very fast (about one microsecond ).
For instance, in practical working it has been found that a furnace return of oï¿½ 504 lb per kilowatt hour is brought down to 0.406 lb per kilowatt hour when the material has been broken up, sorted and packed in air-tight drums. In the tapping process a fixed crucible is used, lined with carbon, the electrode is nearly as big as the crucible and a much higher current density is used.
Furthermore his electrochemical investigations, and particularly his discovery of the important law of electrolysis, that the movement of a certain quantity of electricity through an electrolyte is always accompanied by the transfer of a certain definite quantity of matter from one electrode to another and the liberation at these electrodes of an equivalent weight of the ions, gave foundation for the idea of a definite atomic charge of electricity.
You can see the cathode electrode in the foreground streaming electrons to the grid or slice plate and then onto the aluminum anode plate.
calomel electrode is appropriate.
cathode electrode in order to focus the electron stream into a beam?
Figure 2 shows the effect of erosion as the result of transient cavitation on an aluminum electrode.
chloride electrode was prepared and fixed inside a 10mm long tube.
chromate ions, CrO 4 2- -, moving toward the positive electrode.
concentric with the longitudinal axis of the tungsten electrode.
conductivity sensor features an automatic temperature compensated electrode, encapsulated in an impact-resistant epoxy body.
At the active electrode there is a high current density due to the small area of the electrode.
equilibrium electrochemistry The above are all examples of electrolysis reactions, where an electron is forced in or out of the electrode.
The welding electrode can also lose contact in extreme cases, causing weld splash.
During the stimulation session, self-adhesive electrodes must always be clipped on the special electrode cable of the Compex Mi Sensor system.
The fetal heart rate should be monitored and where available a fetal scalp electrode should be placed.
Metal transfer The transfer of metal across the arc from a consumable electrode to the molten pool.
The blue band is due to positive copper ions, Cu 2+, moving toward the negative electrode.
electrode spacing on the average firing rate of the spark gap.
electrode array inserted in the inner ear.
electrode pads which are attached to the body.
The type of glass used in the pH electrode can be selected for optimal performance.
The released electrons move round in the external part of the circuit to produce the negative charge on the cathode electrode.
Placed into this is a platinum electrode surrounded by a gas tube submerged in the solution, with hydrogen at 1 atm inside.
Metal atoms of a metal electrode can also be oxidized to form positive metal ions which pass into the liquid electrolyte.
Product range includes oxygen electrode and chlorophyll fluorometer products.
The thermal and electrical field distribution in the waveguide of any electrode geometry can be determined.
Tokai Carbon Europe is a stockist of premium grade graphites for EDM electrode, high temperature and mechanical applications.
The standard electrode potential of a half cell,, is defined as the potential difference between it and a standard hydrogen half-cell.
We have used the transparent conductor indium tin oxide to fabricated electrode arrays with approximately 500 electrodes spaced at 60 Am.
Take care not to contact the porcelain insulator or the center electrode as they can be easily damaged.
In the section on electrode kinetics we saw how the electrode voltage can effect the rate of the electron transfer.
Neurons close to the stimulating electrode become very leaky, but fire because of the strong depolarisation.
platinum electrode surrounded by a gas tube submerged in the solution, with hydrogen at 1 atm inside.
porcelain insulator or the center electrode as they can be easily damaged.
However now for the reaction to continue we need a supply of fresh reactant to approach the electrode surface.
reactant concentration at the electrode than in bulk solution.
The CB5 lead is another bipolar lead which has one electrode positioned at V5 and the other over the right scapula.
Scrotum electrode The scrotum electrode The Scrotum Electrode is another of the latest additions to the P.E.S. product line.
self-adhesive electrodes must always be clipped on the special electrode cable of the Compex Mi Sensor system.
The first graph shows the effect of electrode spacing on the average firing rate of the spark gap.
If in a vessel of nitric acid are placed a large platinum plate and a platinum electrode of very small surface such as that produced when an extremely fine platinum wire is slightly immersed in the liquid, and if a current from a single voltaic cell is passed through the electrolytic cell so that the fine wire is the anode or positive pole, then the small surface will be polarized or covered with a film of gas due to electrolysis (fig.
For instance, in practical working it has been found that a furnace return of oÃ¯¿½ 504 lb per kilowatt hour is brought down to 0.406 lb per kilowatt hour when the material has been broken up, sorted and packed in air-tight drums. In the tapping process a fixed crucible is used, lined with carbon, the electrode is nearly as big as the crucible and a much higher current density is used.
In his optical researches, Optiska Undersiikningar, presented to the Stockholm Academy in 1853, he not only pointed out that the electric spark yields two superposed spectra, one from the metal of the electrode and the other from the gas in which it passes, but deduced from Euler's theory of resonance that an incandescent gas emits luminous rays of the same refrangibility as those which it can absorb.
Consequently there will be a lower reactant concentration at the electrode than in bulk solution.
Scrotum Electrode The Scrotum Electrode is another of the latest additions to the P.E.S. product line.
The risk for depth electrodes is approximately 1% per electrode; the incidence of meningitis is higher with subdural grids.
The wire serves the dual purpose of acting as the current-carrying electrode and the weld metal filler wire.
On a plasma, no lines are visible since each pixel cell has its own transistor electrode, lighting the color and image across the screen evenly.
During an EKG, small electrode patches are attached to the skin on the chest.
During an EKG, small electrode patches are attached to the skin on the chest and connected to a computer that measures the heart's electrical impulses and records them in a zigzag patter on a moving strip of paper.
The measurement of fetal heart activity is performed most accurately by attaching an electrode directly to the fetal scalp.
Generally the insertion of a fetal scalp electrode is a safe procedure, but it may occasionally cause umbilical cord prolapse or infection due to early amniotomy.
Problems could also occur if the electrode or IUPC causes trauma to the eye, fetal vessels, umbilical cord, or placenta.
A clinician tunes the speech processor and sets levels of stimulation for each electrode from soft to loud.
"The '10-20 System' of Electrode Placement."
During the DBS procedure, an electrode placed in a precise area of the brain delivers small, electrical shocks to interrupt the abnormal brain activity that leads to symptoms.
The electrode has four metal contacts that can be used in different combinations.
The electrode is connected by a wire to a pacemaker-like device implanted under the skin in the chest.
In this method, a device known as the fetal scalp electrode is placed into the vagina and is placed on top of the baby's head, measuring the heart rate.
ESAB was founded by Oscar Kjellberg after he invented the covered welding electrode in 1904.
Thus, if the molecule of a substance in solution is represented by AB, Grotthus considered a chain of AB molecules to exist from one electrode to the other.
In order that the current should be maintained, and the electromotive force of the cell remain constant during action, it is necessary to ensure that the changes in the cell, chemical or other, which produce the current, should neither destroy the difference between the electrodes, nor coat either electrode with a non-conducting layer through which the current cannot pass.
When an alkaline chloride, say sodium chloride, is electrolysed with one electrode immersed in a porous cell, while caustic soda is formed at the cathode, chlorine is deposited at the anode.
Hydrogen and oxygen may also be produced electrolytically as gases, and their respective reducing and oxidizing powers at the moment of deposition on the electrode are frequently used in the laboratory, and to some extent industrially, chiefly in the field of organic chemistry.
Experiment showed, however, that instead of only potash appearing at the negative electrode, hydrogen is also liberated; this is inexplicable by Berzelius's theory, but readily explained by the " hydrogen-acid " theory.
By this theory potassium is liberated at the negative electrode and combines immediately with water to form potash and hydrogen.
Faraday discovered the existence of a dark space round the negative electrode which is usually known as the " Faraday dark space."
If, however, one electrode of this cell is connected to the earth and the other to a receiving antenna and electric waves allowed to fall on the antenna, the oscillations passing through the electrolytic cell will remove the polarization and L temporarily decrease the resistance of the cell.
A highly insulated tube contains a little mercury, which is used as a negative electrode, and the tube also has sealed through the glass a platinum wire carrying an iron plate as an anode.
The box is thus entirely closed at the front, while the front carbon disk, which constitutes an electrode, is perfectly free to follow the motions of the diaphragm.
In the case we have chosen, the solution becomes stronger near the anode, or electrode at which the current enters, and weaker near the cathode, or electrode at which it leaves the solution.
Under the series system only the first anode and the last cathode are connected to the conductors; between these are suspended, isolated from one another, a number of intermediate bi-polar electrode plates of raw copper, each of these plates acting on one side as a cathode, receiving a deposit of copper, and on the other as an anode, passing into solution; the voltage between the terminals of the tank will be as many times as great as that between a single pair of plates as there are spaces between electrodes in the tank.
First one and then the other conductor is connected with the electrode of the lower or movable plate, which is moved by the screw until the index attached to the attracted disk shows it to be in the sighted position.
Faraday observed that a large drop of mercury, resting on the flat bottom of a vessel containing dilute acid, changes its form in a remarkable way when connected with one of the electrodes of a battery, the other electrode being placed in the acid.
The word usage examples above have been gathered from various sources to reflect current and historial usage. They do not represent the opinions of YourDictionary.com.