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Insert details about how a CRT operates

How a CRT Operates

Signal Amplification

Sync Separation

Vertical Oscillator

Vertical oscillator must convert the vertical sync pulse into a 50% duty cycle square wave for the horizontal output oscillator. Most chassis are based off of a heartly style voltage controlled oscillator with the flyback pulses and sync pulses being used to adjust the voltage going into the oscillator. if sync pulse is slow or fast the voltage raises or lowers changing the frequency.

Horizontal Oscillator

Vertical Amplification

Flyback and horizontal coil Control

The flyback circuit consists of a LC circuit and horizontal output transistor (HOT). When the transistor turns on current begins to build in the circuit relatively uniformly until the HOT turns off. When the HOT turns off the magnetic field collapses and sends all of its energy into the fly back capacitor. this then causes a spike in voltage causing the coil to begin conducting in the opposite direction. This is then repeated as the HOT turns back on.

Waveform of flyback circuit. Red = 15khz square wave driving HOT. Green = current going through coil. Blue = voltage at HOT Drain.

Example schematic of flyback circuit.

Focus Control

Single Focus

Dual Focus

Trinitron Focus and Convergence

Differences between Shadow Mask and Trinitron Tubes

Differences between "Flat" and traditional tubes

Additional Reading

CRT Online References Is the page I am dedicating to any and all references to how TVs and monitor chassis operate.

crt_chassis_theory_of_operation.txt · Last modified: 2023/09/20 20:16 by jake

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