Kategorier: Alle - television - conduction - electrons - resistance

av peter hill 14 år siden

384

ideas to implementation

The production of electrons through the interaction of light, such as in solar cells, involves various physical principles. Superconductors, materials that exhibit zero electrical resistance, play a significant role in advanced technologies.

ideas to implementation

ideas to implementation

Superconductor

Conduction and resistance
Resistance
Conduction
Bragg

outline the methods used by the Braggs to determine crystal structure

  • Bragg used x-rays (100 ev Photons)
  • X-rays are made by electrons smashing metals
  • x-rays reflect of atoms
  • spaced atoms cause interference



  • Semiconductor

    Production of electrons with light - solar cells

    Electron Tube - TV

    Applications

    •outline the role of:

    ◦electrodes in the electron gun

    ◦the deflection plates or coils

    ◦the fluorescent screen

    in the cathode ray tube of conventional TV displays and oscilloscopes

    fluorescent screen

    Makes light when hit with electrons

    Colour TV has clusters of three phosphors for observation at a distance

    CrO

    Single colour green or blue to read at close distance

    Deflection

    Old Televisions

    External Coils, Cheaper but designed to "RASTER"

    Internal E field Plates, Expensive, but highly sensitive for science

    Electron gun and Plates

  • Electron gun has a very high field as the lines converge on a point. Heat also kicks the electrons of the tip.
  • The acceleration anode give the electrons a high fixed speed, which provides the energy that is later converted into light.
  • Further Plates act as an electrostatic lens that curves electrons moving at an angle to the axis back into form an image of the gun on the screen.

  • Old Television

    Three guns for three colours, and designed to switch current pixel to pixel

    CRO

    Single gun, with focus designed for steady intensity.

    E B balance e/m

    F = Eq...........................................(1)

    F =qvB..........................................(2)

    F=mv^2/r (with no electric field).......(3)

    also E= V/d

    (1) = (2) gives v

    (2) = (3) + v + r measured gives e/m

    or (1) = (2) = (3) gives q/m = E/rB^2

    Cathode Rays - Particle
    Discharge tubes