What is a Nixie tube?
A Nixie tube is an electronic component used to display a fixed set of characters, typically letters or numbers. It looks like a vacuum tube but functions more like a neon lamp. The tube has one anode or positive terminal and several cathodes, one for each character you want to display. Individual characters can be displayed by applying 170 volts DC between the anode and one of the cathodes. A current limiting resistor of around 47K is required between the anode of the Nixie tube and DC power supply. Each Nixie tube only requires a few milliamps to work. The Nixie tubes I used for this project are Russian made Type IN-12A . This Nixie tube uses an inverted 2 to display 5, most likely to reduce manufacturing costs. A Nixie tube typically displays characters in an orange or reddish glow around the character shaped cathode.
Where do I get Nixie tubes?
Where do I get the rest of the parts for the project?
Most parts like resistors and capacitors I already had. Most vendors require a minimum order when you order discrete components. So say I only need one 1Meg Watt resistor for a project. I would have to purchase at least ten to meet their minimum requirement.
Giving Credit where credit is due!
The Nixie Clock discussed in this Lens is not of my own design. It is based on schematics from Mike Harrison in the UK. My creativeness was used in the implementation of Mike’s Nixie Clock design. Below is the web link to his site.
Caution, only experienced electronic hobbyists should attempt to build this circuit!
My Isolation Transformer:
The Division Bell:
I broke the Nixie clock circuit up into five circuit boards:Power Supply board - provides the necessary voltages to the other circuits.Lower Digit Board - Drives the Nixie tubes that display seconds.Upper Digit Board - Drive the Nixie tubes that display minutes and hours.Colon Driver Boards - There are two of them, these drive neon bulbs to blink at a 1HZ interval to act as the colons between hours, minutes, and seconds.
Power Supply Board Build:
Power Supply Board Testing:
Nixie Tube Testing:
Digit Board Assembly:
Building the Lower Digit Board:
Lower Digit Board Testing:
Building the Colon Driver Board:
Colon Driver Board Testing:
The Display Case:
Nixie Tube Mounting:
Nixie Tube Mounting (Continued):
Addition of resistors to the Digit boards: - I needed to find a place for the 33K resistors that connect to the Base of the driver transistors. The driver trans
Upper Digit Board (Added 33K resistors are circled in red)
Machining the Display Case Base:
Mounting the Nixie Driver Transistors:
Wiring the Time Set Switches:
Wiring Phase 1:
Testing Phase 1:
Wiring Phase 2:
Testing Phase 2:
Electrical Isolation Test:
Complete! - Here are pictures of my completed Nixie Clock with the plastic display cover installed. I use four brass set screws to keep the cover in place. I lo
Video of my Nixie Clock in action!
Who Writes This Blog?
John is an IT professional from Cleveland, OH who enjoys amateur radio, ham radio, metal detecting,
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