Unsa ang Cathode Ray Oscilloscope (CRO)

Ano ang Cathode Ray Oscilloscope (CRO)?

Pahayag

Ang cathode ray oscilloscope (CRO) usa ka elektrikal nga instrumento para sa pag-suway, pag-analisa, ug pagpakita sa mga waveform ug uban pang elektroniko/electrical nga mga phenomena. Isip usa ka high-speed X-Y plotter, ipakita kini ang input signal labi na sa usa ka siguro nga oras. Kaya kini mao ang pag-analisa sa mga waveform, transient phenomena, ug time-varying quantities sa wide frequency range (gikan sa kaayo ka baho hangtod sa radio frequencies), ug nag-operate kini sa basehan sa voltage. Ang uban pang physical quantities (current, strain, etc.) mahimo mopag-convert ngadto sa voltage pinaagi sa transducers aron mapakita.

Key Operation

Ang luminous spot (gikan sa electron beam nga nahitabo sa fluorescent screen) mogalilis sa display batasan sa input voltages. Ang standard CRO gamiton ang internal horizontal ramp voltage ("time base") alang sa left-to-right horizontal movement, uban ang vertical movement kontrolado sa voltage under test, naghuhuman og stationary viewing sa fast-varying signals.

Construction

Main components:

• Cathode Ray Tube (CRT):Usa ka vacuum tube nga nag-convert sa electrical to visual signals, may elektro gun ug electrostatic deflection plates (vertical/horizontal). Ang gun mag-produce og focused, high-speed electron beam; ang plates mogalilis sa beam independent para sa screen positioning.

• Electronic Gun Assembly:Emits ug shapes the electron beam, including heater, cathode (barium/strontium-coated for electron emission), control grid (regulates beam intensity via negative potential), ug anodes (for acceleration at ~1500V). Focusing uses electrostatic methods (standard in CROs).

• Deflecting Plates:Duha ka pairs: “Y plates” (vertical) ug “X plates” (horizontal) kontrolado ang beam movement.

• Fluorescent Screen:CRT faceplate (flat for small, curved for large screens) coated with phosphor. Electrons striking it cause fluorescence (light emission).

• Glass Envelope:Highly evacuated, cone-shaped. Inner surface has aquadag (conductive coating connected to the accelerating anode) to aid electron focusing.

Working Principle

Ang electrons gikan sa cathode mogalilis sa control grid (negative potential adjusts intensity). Accelerated by anodes, focused, and deflected by plates per input voltages, they hit the screen, creating a visible spot to trace waveforms.

After passing through the control grid, the electron beam travels through the focusing and accelerating anodes. The accelerating anodes, at a high positive potential, converge the beam to a point on the screen.

Emerging from the accelerating anode, the beam then comes under the influence of the deflecting plates. With zero potential on the deflecting plates, the beam forms a spot at the center of the screen. Applying a voltage to the vertical deflecting plates deflects the electron beam upward; applying a voltage to the horizontal deflecting plates deflects the light spot horizontally.