Understanding Oscilloscope CRT Displays and Waveforms

CRT Screen Dimensions

The dimensions of the CRT screen are now standard in most instruments, measuring 10 cm in the horizontal axis (X) by 8 cm in the vertical (Y). On the screen, divisions of 1 cm square are recorded, either directly on the CRT or on a superimposed part featuring a grid of 80 cm square. This grid serves as the reference for the signal representation applied to the oscilloscope.

Appliance Description

The device consists of an evacuated glass tube containing:

• An electron beam dispenser at one end.
• A screen coated with phosphorescent material at the other end.
• Two pairs of parallel plates (one horizontal and one vertical).

Beam Deviation Formula

The beam deviation experienced is defined as:

y = (1/2) * (m/d) * (v0^2) * (E/V)

RMS Voltage Measurement

The RMS voltage is calculated as:

V_LFGosc = V_OSC / √2

Understanding Waves

A wave is a general term for a pattern that repeats over time. Common examples include sound, oceanic, and voltage waves. An oscilloscope measures voltage waveforms, where the horizontal axis (X) represents time and the vertical axis (Y) represents amplitude. This allows for the visualization of voltage changes over time.

Types of Waves

• Sine Waves: Fundamental waves used for various applications.
• Square Waves: Waves that transition between two voltage states at regular, short intervals.
• Rectangular Waves: Similar to square waves but with unequal intervals for high and low states.
• Triangular and Sawtooth Waves: Occur in circuits designed to control voltages linearly.

Additional Signal Concepts

• Pulses and Flanks (Steps)
• Cycle: The smallest repeating part of a wave over time.
• Phase
• Signal Generator: The central unit for generating test quantities, forming pilot quantities for routing digital amplifiers.