Search results
Results from the WOW.Com Content Network
The positive ions were accelerated by the electric field toward the cathode, and when they collided with it they knocked electrons out of its surface; these were the cathode rays. Modern vacuum tubes use thermionic emission , in which the cathode is made of a thin wire filament which is heated by a separate electric current passing through it.
Since it is a hot cathode, it is prone to cathode poisoning, which is the formation of a positive ion layer that prevents the cathode from emitting electrons, reducing image brightness significantly or completely and causing focus and intensity to be affected by the frequency of the video signal preventing detailed images from being displayed ...
The first attempt to measure the mass-to-charge ratio of cathode ray particles, assuming them to be ions, was made in 1884-1890 by German-born British physicist Arthur Schuster. He put an upper limit of 10^10 coul/kg, [ 5 ] but even that resulted in much greater value than expected, so little credence was given to his calculations at the time.
A battery or galvanic cell in use has a cathode that is the positive terminal since that is where conventional current flows out of the device. This outward current is carried internally by positive ions moving from the electrolyte to the positive cathode (chemical energy is responsible for this "uphill" motion). It is continued externally by ...
Significantly, the rays from every cathode yielded the same mass-to-charge ratio. This is in contrast to anode rays (now known to arise from positive ions emitted by the anode), where the mass-to-charge ratio varies from anode-to-anode. Thomson himself remained critical of what his work established, in his Nobel Prize acceptance speech ...
Since it is a hot cathode, it is prone to cathode poisoning, which is the formation of a positive ion layer that prevents the cathode from emitting electrons, reducing image brightness significantly or completely and causing focus and intensity to be affected by the frequency of the video signal preventing detailed images from being displayed ...
The study of gas discharges in the mid 19th century led to the discovery of anode and cathode rays, which turned out to be positive ions and electrons. Improved capabilities in the separation of these positive ions enabled the discovery of stable isotopes of the elements.
Anode ray tube showing the rays passing through the perforated cathode and causing the pink glow above it. Anode ray tube, turned-off condition. An anode ray (also positive ray or canal ray) is a beam of positive ions that is created by certain types of gas-discharge tubes.