Yes, that marginal test circuit is good for checking the pulse shape. I've never seen the circuit with the 10k potentiometer mentioned anywhere though, not even in Philips literature, but it weeds out tubes with what I guess is low emission from the cathode.
I'd use the a1 electrode as you can then check if a tube either has counted more than one step at a time and correct it, or just note that that tube sometimes steps more than one step. /Martin On Sunday, 17 February 2019 16:47:41 UTC+1, Sgitheach wrote: > > Hi > > Yes, I understand that the voltages scale, I suppose that is expected. In > early experiments I found some tubes would count with, say, 320V anode > voltage but not 300V. This was when I was not forming the sawtooth step > pulse correctly. > > In the section on running an E1T counter at 100kHz, Dance says "It is > important that the first E1T tube should be selected carefully." He > presents a test circuit to select high frequency tubes (100kHz) and the > remainder that don't pass the test are used for other counts (< 30kHz). > > I don't use the A1 output anode to detect a count of '10' but maintain a > position list in the firmware and send a reset pulse to move to '0' when > you try step beyond '9'. > > Thanks > > Grahame > On 17/02/2019 15:17, Dekatron42 wrote: > > Most of the components where kept identical, even the cathode resistor, > but the resistor on the a1 output anode was raised to some 560k as this > signal was mostly used to directly reset the E1T via a capacitor directly > to the D' and a2 electrodes, the capacitor value was selected according to > what counting frequency you were after (330pF-1nF). The other voltages were > also raised accordingly 15.8V(11.9V), 208V & 226V (used for limits for the > pulse voltage on the D electrode). > > Sticking to the datasheet is the way to go when you count at slow speeds, > below the usual limit of 30kHz, but with troublesome tubes the extra 10k > potentiometer is a good way to weed out the really bad ones, just as when > you want to weed out the ones that don't count much further than 30kHz and > the ones that sometimes miss a counting step but works fine otherwise. > > Really nice that the case design will have different possibilities! > > /Martin > -- > 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] <javascript:>. > To post to this group, send email to [email protected] > <javascript:>. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/252715da-5fd1-4883-8f02-441caa3305f3%40googlegroups.com > > <https://groups.google.com/d/msgid/neonixie-l/252715da-5fd1-4883-8f02-441caa3305f3%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 an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/0ad78e51-ddf4-4714-a153-222132843041%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
