Its the 10 hours position ? Not the 10s minutes or 10s second ? Blanking those would just look weird. If so, that digit only light 0 & 1, in 12-hour mode, or 0, 1, & 2 in 24-hour mode. Why then use the 74141 at all ? If you do, then a quick fix would be to put a resistor (2 or 3, depending on 12/24 hr mode) across the anode, to the connected cathodes. Leave all other cathodes (3-9) disconnected. Calculate it so the drop across the anode-cathode is less than 120V. Say the anode resistor is 10K, the supply is 180V, and the zener break-over is 55V. 180V-120V-55V=5V. That means calculate the bleed cuurent so 5V is dropped across the anode resistor. If its 10K, the bleed is 5V/10K=0.5mA (500uA). This "bleed" is the "off" current. 120V/500uA=240K. So stick 220Ks across anode to each used cathode. That's ANODE, NOT Supply !
If its 12-hour mode try this scheme: http://threeneurons.files.wordpress.com/2011/08/hour_blk.gif Found on this page: http://threeneurons.wordpress.com/nixie-power-supply/ On Tuesday, June 26, 2012 2:25:59 PM UTC-7, Jonathan wrote: > > Hi all, > > I'm making my first clock that has to be set by the user instead of self > setting. And the leading digit needsl to be blanked, as the woman it is for > doesn't want to see the zero. > > Anyway, I am using the blanking feature of the 74141 for the first time. > It seems that some of them don't blank as well as others and to get them > all to blank I have to dial the anode voltage down or lower tje pwm duty > cycle which prevents max brightness during the day. One of the 74141s > blanks well and so does a Russian equivalent that i have. So, am i doing > something wrong and is there anything I can do about it? I suppose I can > cherry pick through my stash for chips that blank well. > > Thanks! > > Jonathan > > ***************************** > Some people are like a slinky - not really good for anything but you still > can't help but smile when you shove them down the stairs. > ***************************** > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To view this discussion on the web, visit https://groups.google.com/d/msg/neonixie-l/-/kwi1mZ5aXrsJ. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
