Search results
Results from the WOW.Com Content Network
An electric battery is a source of electric power consisting of one or more electrochemical cells with external connections [1] for powering electrical devices. When a battery is supplying power, its positive terminal is the cathode and its negative terminal is the anode. [2] The terminal marked negative is the source of electrons.
The term on the left is the rate of change of the charge density ρ at a point. The term on the right is the divergence of the current density J at the same point. The equation equates these two factors, which says that the only way for the charge density at a point to change is for a current of charge to flow into or out of the point.
A 1919 illustration of a Leclanché cell. The Leclanché cell is a battery invented and patented by the French scientist Georges Leclanché in 1866. [1] [2] [3] The battery contained a conducting solution (electrolyte) of ammonium chloride, a cathode (positive terminal) of carbon, a depolarizer of manganese dioxide (oxidizer), and an anode (negative terminal) of zinc (reductant).
Dielectric relaxation in changing electric fields could be considered analogous to hysteresis in changing magnetic fields (e.g., in inductor or transformer cores). Relaxation in general is a delay or lag in the response of a linear system , and therefore dielectric relaxation is measured relative to the expected linear steady state (equilibrium ...
Electric charge is a conserved property: the net charge of an isolated system, the quantity of positive charge minus the amount of negative charge, cannot change. Electric charge is carried by subatomic particles. In ordinary matter, negative charge is carried by electrons, and positive charge is carried by the protons in the nuclei of atoms ...
Einstein was awarded the Nobel Prize in Physics in 1921 for "his discovery of the law of the photoelectric effect". [27] The photoelectric effect is also employed in photocells such as can be found in solar panels. The first solid-state device was the "cat's-whisker detector" first used in the 1900s in radio
Electrons have a negative electrical charge, so the movement of electrons is opposite to that of the conventional current flow. Consequently, the mnemonic cathode current departs also means that electrons flow into the device's cathode from the external circuit. For example, the end of a household battery marked with a + (plus) is the cathode.
In the strictest sense, a battery is a set of two or more galvanic cells that are connected in series to form a single source of voltage. For instance, a typical 12 V lead–acid battery has six galvanic cells connected in series, with the anodes composed of lead and cathodes composed of lead dioxide, both immersed in sulfuric acid.