Start with a known open-source project like the "CRT Clock by J. D. Paul" (available on GitHub). Study the HV section carefully. Build the low-voltage logic first, test the CRT filament, then apply HV last.
If you don't turn the beam off while moving between digits, you will see "flyback lines" connecting the numbers. The schematic must include a transistor that shorts G1 to -50V during jumps. Part 6: Putting It All Together – A Complete Bill of Materials (BOM) Based on a typical electrostatic CRT clock schematic (e.g., "SNTP-CRT" by David Forbes), here is what you need: Crt Clock Schematic
// Pseudo-code for vector drawing void draw_digit(uint8_t digit, int x_center, int y_center) // Retrieve coordinate list for 'digit' Point *points = digit_shapes[digit]; for (int i = 0; i < points->length; i++) setDAC(X, x_center + points[i].x); setDAC(Y, y_center + points[i].y); Z_ON(); // Beam on while moving between coordinates delayMicroseconds(10); Z_OFF(); // Move to next digit with beam off Start with a known open-source project like the
Introduction In an age dominated by OLEDs and TFT touchscreens, the humble Cathode Ray Tube (CRT) has become a relic of a bygone analog era. Yet, for the daring electronic hobbyist, the CRT offers a mesmerizing aesthetic: glowing green or amber phosphor, sharp vectors, and the distinct whine of a flyback transformer. Study the HV section carefully
If you succeed, you will own the most mesmerizing conversation piece on any desk—a ticking, glowing monument to the analog soul hiding inside digital data. For a complete, ready-to-print PDF schematic, please ensure you adhere to local electrical codes. When in doubt, use an oscilloscope transformer (isolation type) for your mains input.
Note: Old TV tubes require 15kV. Do not use TV tubes for desk clocks. Most efficient schematics use a Royer oscillator (ZVS) to drive a ferrite core flyback transformer.