A standard digital clock relies on multiplexed LEDs or liquid crystals to turn pre-shaped segments on and off. A CRT, however, has no built-in segments. It features a single electron gun that shoots a stream of electrons at a phosphor-coated screen.
Architecturally, hobbyist CRT clocks generally use one of two display methods: or Vector (XY) Plotting . Raster scanning mimics a traditional television by sweeping the beam across the entire screen line by line. Vector plotting treats the CRT like an oscilloscope, drawing characters directly with continuous geometric lines. Vector plotting is highly preferred by hobbyists because it requires lower bandwidth and yields sharp, retro-stylized numbers. Core Circuit Modules in a CRT Clock Schematic Crt Clock Schematic
The brain of the clock generates the vector paths for the numbers. A standard digital clock relies on multiplexed LEDs
Used by most small hobbyist CRTs. It relies on voltage differentials on deflection plates. The circuit uses high-voltage, high-speed transistors (like the MJE340/MJE350 pair) configured as differential operational amplifiers. Architecturally, hobbyist CRT clocks generally use one of
The final anode voltage (post-focus) is lethal.
This block acts as the brains of the clock, calculating time and translating it into coordinate data.
