Crt Clock Schematic Verified Now

The low-voltage signals from the microcontroller must be boosted to high voltage (~100V-300V) to move the electron beam across the screen. This is often done using vacuum tubes like the or high-voltage transistors in a cascode configuration. Filament Supply:

To move the beam to the corner of the screen, the deflection plates require a differential voltage swing of roughly ±50V to ±100V. Your microcontroller outputs 0V to 5V. You need an amplifier.