Crt Clock Schematic May 2026

Building a CRT Clock: Understanding the Schematic

There’s something mesmerizing about a glowing cathode-ray tube displaying the time. Unlike a simple LCD or LED clock, a CRT clock is a hybrid of retro hardware and modern microcontroller control. Whether you salvage a small 3-inch green-phosphor tube from an old viewfinder or use a 5-inch oscilloscope tube, the heart of the project lies in the schematic.

Filament Regulation: The schematic includes a specific low-voltage circuit (often using an LM317 regulator) to power the CRT’s heater/filament at exactly 6.3V, ensuring the tube emits electrons without burning out the heater. Crt Clock Schematic

The Blanking Circuit

The schematic requires a fast comparator. The microcontroller sends a "BLANK" signal (5V logic). Building a CRT Clock: Understanding the Schematic There’s

4. Full Component List (per schematic)

| Section | Key Parts | |---------|------------| | HV Supply | Flyback transformer, IRF740 MOSFET, 555 timer, 1N4007 diodes | | Deflection X/Y | OPA551 or TDA2030 (x4), ±50V rails, 10k resistors | | Z-axis | 2N3904/2N3906, 470Ω, 10k pot | | MCU | Arduino Nano, MCP4922 DAC (12-bit, 2 ch) | | RTC | DS3231 module | | Power | 12V/2A adapter + 7815/7915 for analog rails | Filament Regulation : The schematic includes a specific

A CRT clock doesn't use pixels; it uses an electron beam that scans a phosphor-coated screen. By controlling the X (horizontal) Y (vertical)