Electronic Gurus - I really hope someone can help me here. I decided a little while ago to build my own nixie clock. For those that are unfamiliar, please take a quick look (this one is not mine): http://www.youtube.com/watch?v=KpYnzbQG7H0.
Before I describe my problem, let me explain how my circuit is supposed to work. To save pins on the microprocessor, I will only power one bulb at a given time. The processor will cycle which bulb is lit so quickly that it should appear that all the bulbs are lit at once (many inexpensive modern LED clocks use this type of circuit). For this to work, I have wired all the cathodes on the bulbs together and left the anode leads independent. The bulb receiving power to its anode should be the bulb that illuminates. Grounding a specific cathode lead would select the digit.
The problem is that whichever bulb I power, there is always a second bulb partially lit (showing the same digit). I'm not really sure how this is possible. The other bulb is grounded on the cathode but is not hooked up to any positive power on the anode. My best guess is that there is some sort of electrical interference causing the bulb to illuminate.
I posted a video to YouTube to show what I'm talking about: http://www.youtube.com/watch?v=gDAx2vqAWz0
I would really appreciate any help you guys could provide.
Thanks,
SMB84
Before I describe my problem, let me explain how my circuit is supposed to work. To save pins on the microprocessor, I will only power one bulb at a given time. The processor will cycle which bulb is lit so quickly that it should appear that all the bulbs are lit at once (many inexpensive modern LED clocks use this type of circuit). For this to work, I have wired all the cathodes on the bulbs together and left the anode leads independent. The bulb receiving power to its anode should be the bulb that illuminates. Grounding a specific cathode lead would select the digit.
The problem is that whichever bulb I power, there is always a second bulb partially lit (showing the same digit). I'm not really sure how this is possible. The other bulb is grounded on the cathode but is not hooked up to any positive power on the anode. My best guess is that there is some sort of electrical interference causing the bulb to illuminate.
I posted a video to YouTube to show what I'm talking about: http://www.youtube.com/watch?v=gDAx2vqAWz0
I would really appreciate any help you guys could provide.
Thanks,
SMB84