But interestingly it is working within specified current but without the anode resistor.
I am not sure what advantage I would get increasing the anode voltage to 190v and having a resistor drop 20v to leave my 170v and 8ma current flow through the tube. Presumably the only advantage would perhaps be quicker ignition? David On Tue, 22 Jan 2019, 19:22 Bill van Dijk <[email protected] wrote: > You can see why the specs recommend 190V as the recommended for > multiplexed mode. Below 190 to 200V you will not get it to work properly. > > > > Bill > > > > *From:* [email protected] [mailto:[email protected]] *On > Behalf Of *David Pye > *Sent:* Monday, January 21, 2019 4:35 PM > *To:* neonixie-l <[email protected]> > *Subject:* [neonixie-l] Pulsed operation and anode current > > > > Hi everyone and thanks for letting me join the group! > > I am trying to build a multiplexed clock using IN-14 nixies, and have run > into a problem. > > > > In order to get acceptable brightness, in pulsed mode, the current has to > be much higher to make up for the fact that it is only on for short pulses. > > > > From the data sheet https://tubehobby.com/datasheets/in14.pdf : > > > > *For 'direct drive':* > > > > *Firing voltage (no more than) 170V * > > *Current for digits (no more than) 2.5mA * > > > > *Multiplex mode :* > > > > *Power supply voltage 190V * > > *Average current for digits 0.7 - 1.5mA * > > *Pulse current for digits 7 – 13mA * > > *Pulse width (no less than) 70µS * > > *Period 1 – 1.8 kHz * > > > > However, I cannot achieve those currents. > > > > When I tried calculating the anode resistor value I wanted, (using > http://www.csgnetwork.com/anoderescalc.html) - using supply 170, sustain > ~130V, current 13mA, it suggests an anode resistor of around 2.6K, but when > trying this value, I found that the current that flowed was more like 6mA, > and the voltage across the resistor was 10V, and 160V across the nixie. > > > > For further testing, I briefly tried WITHOUT *ANY* anode resistor. It > was extremely bright, with an anode current of around 8mA - and not more! > I checked the PSU voltage while doing this, and it was still at 170V, > so the voltage wasn't sagging. > > > > Obviously this would kill the tube if left on for any length of time, but > for testing purposes it illustrates my issue. > > > > I've tried briefly with a couple of IN14s and even an IN12, and the above > is roughly consistent. > > > > So this leads me to a couple of questions: > > > > 1) Seeing as the data sheet seems to take care to specify a higher > voltage for multiplex mode, am I to assume that for some weird reason, the > nixies don't behave as I'd expect when you are trying to flow larger > currents? ie they don't actually try to pull the supply voltage down all > the way to Vsustain? Do I need to increase Vsupply to 190V to achieve > higher currents e.g 13mA? > > 2) If I am happy with the current of 8-9mA at 170V without an anode > resistor while multiplexing, does it mean that I can (in this specific > application) get away without an anode resistor then? > > > Suggestions welcome! > > Thanks > > > David > > -- > You received this message because you are subscribed to the Google Groups > "neonixie-l" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/7f8e1fd5-d144-452b-8805-35847d8204f4%40googlegroups.com > <https://groups.google.com/d/msgid/neonixie-l/7f8e1fd5-d144-452b-8805-35847d8204f4%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > > -- > You received this message because you are subscribed to the Google Groups > "neonixie-l" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/00fe01d4b287%24d1ddcc50%24759964f0%24%40gmail.com > <https://groups.google.com/d/msgid/neonixie-l/00fe01d4b287%24d1ddcc50%24759964f0%24%40gmail.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/CAOQ6x0GTLY1bwVwvqyYSsVc3s%2BvWEAkFXukayouoB31ecdKzsg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
