IGCSE+Cathode-ray+oscilloscopes


 * __Cathode-ray oscilloscopes __**

• Describe the production and detection of cathode rays Cathode rays are __b eams __ of __e lectrons __ produced by __t hermionic __ emission in a vacuum tube. They are __d eflected __ in electric fields. The deflection of beams of charged particles is used in __ television __ tubes, cathode-ray o__ scilloscopes __.
 * (a) Cathode rays **

• Describe their deflection in electric fields A beam of charged particles experience a force if it passes through a magnetic field. The deflection of the force is given by Fleming's__ left- __hand rule.

• State that the particles emitted in thermionic emission are electrons The process that a cathode ray tube, which coated with a metal, releases electrons when heated.

• Describe (in outline) the basic structure and action of a cathode-ray oscilloscope (detailed circuits are not required) • Use and describe the use of a [|cathode-ray oscilloscope] to display waveforms
 * (b) Simple treatment of cathode-ray oscilloscope **
 * Supplement **



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Keywords: Cathode: the negatively charged electrode by which electrons enter an electrical device. the __e lectrode __ negatives repelled from. Anode: the positively charged electrode by which the electrons leave a device. The opposite of cathode. Rays: a stream of __ particles __ Electrode: a conductor through which electricity enters or leaves an object, substance, or region. Oscilloscope: a device that can observe constant variation of signal voltages. Deflect: to change of direction. Y plates: Vertical deflecting plates. P.d. control. X plates: Horizontal deflecting plates. Time base control. Thermionic: of or relating to electrons emitted from a substance at very high temperature. Thermionic emission is the discharge of electrons from heated materials.

[|Oscilloscope revision questions]