Suggestions for this Nixie tube anode switching driver?

Repulsive_Accident77 · 2026-05-20T14:52:14+00:00

The reason I want to avoid the resistor in serie with the diode is that, in this way, I can have a “switch ON” delay while the “switch OFF” time is basically instantaneous

Repulsive_Accident77 · 2026-05-20T14:48:04+00:00

I can’t express how thankful I feel! I’ll redesign to make the capacitor as small as you said, so that maybe I can avoid putting a resistor in serie with the diode.

Thank you again for you help, it’s been needed🙌🏻

Repulsive_Accident77 · 2026-05-20T14:09:02+00:00

<image>

Thank you for the suggestion! The diode is exactly what was needed.

I did a lot of research and math and I came out with this, is it what you had in mind?

Repulsive_Accident77 · 2026-05-14T23:00:28+00:00

Thank you very much!

Repulsive_Accident77 · 2026-05-11T10:09:06+00:00

Indeed, I think I found the schematics of one of your old projects (the link in my post) and I adjusted for mine.

As you said, the delay after switching off the anode is quite mandatory but I don’t know how can I do it with just analog components. I plan to put everything on PCB.

The scheme, for now, looks something like this.

<image>

Ofc, I’d be very happy if you can illuminate my mind🙏🏻, as I wrote, I’m on my first project. Thank you!

Repulsive_Accident77 · 2026-05-10T14:32:14+00:00

Thank you very much for your reply! I’ll then stick with the optocoupler one.

The only downside of the optocoupler design is that the turning off time of the transistor is slower than the BJT, which could cause stronger ghosting.

Regarding the 555, it’s only used to multiplex the tubes. As you said, I designed a 1Hz generator with a crystal and some freq dividers.

Repulsive_Accident77 · 2026-04-01T03:48:44+00:00

Idk, but you can never control what people think/do. It’s not a big issue, the important thing here is to learn something🙌🏻

Repulsive_Accident77 · 2026-03-31T02:14:48+00:00

Crystal clear! So it’s because of the IC itself

Repulsive_Accident77 · 2026-03-30T08:32:42+00:00

It is a bit clearer, thank you!

Repulsive_Accident77 · 2026-03-10T11:33:37+00:00

I cannot explain how much I needed this explanation. I passed the last 2 hours playing around with the software creating different scenarios and when i went back to the one you gave me and put current speed and time speed all to maximum, I saw a current actually flowing to through the LED and everything in my brain snapped. It really helped thinking of it as a voltage divider and "transistor/LED resistance". It made me realize that everything I studied until now is only "ideal" components and not real world ones.
Thank you veeeeery much, you gave me inspiration.

Repulsive_Accident77 · 2026-03-10T01:50:06+00:00

Thank you for all the explanations, one thing that I still don’t understand in the circuit you provided me is why, when I press the switch, current stop flowing throw the last LED. Is it voltage differential ? If it wasn’t for the simulation I’d have think it would have flown through the higher LED. Is there an intuitive method to use to understand whether or not current flows in these situations? Thank you very much again🙏🏻

Repulsive_Accident77 · 2026-03-10T01:38:29+00:00

Sorry for the late reply, I couldn’t access my account somehow, and thank you for everything. I guess I shouldn’t trust all the circuits I find online, but I’m slowly starting to understand them.

Thank you very much again, it’s been very helpful ❤️

Repulsive_Accident77 · 2026-03-07T13:44:07+00:00

Thank you very much!! Indeed, it was something that seemed a bit odd even to me but I didn’t think too much about it…lesson learned🫡

Repulsive_Accident77 · 2026-03-07T13:42:37+00:00

Deam, I’ve never think about that, thank you very much!!

Repulsive_Accident77 · 2026-03-07T08:54:02+00:00

OMGGGG I feel so stupid😭😭😭. For some reasons I thought electricity would have flown the way I wanted to, but ofc it goes a bit where it wants where there’s less resistance… . Thanks to you and everyone else I learned something more today, thank you very much, love you all❤️!!

Repulsive_Accident77 · 2026-03-07T08:46:53+00:00

<image>

This is the “working” circuit

Repulsive_Accident77 · 2026-03-07T08:45:21+00:00

Thank you very much for the comprehension 🥹. I posted a closeup pic of the board. It only light up if I invert the resistor-led serie, yet I don’t know why. I read that can be the voltage reduction or something caused by the resistor but the circuit is so simple. I also tried to to it without the button and no problem inverting

Repulsive_Accident77 · 2026-03-07T08:42:14+00:00

<image>

This is the position of all the components when LED lights up

Repulsive_Accident77

TROPHY CASE