On Tuesday, June 14, 2016 at 12:50:06 PM UTC-7, Mike Allen wrote: > > Do you guys know about this blue dot problem?
The "blue dot", is only a minor aesthetic issue. It occurs on IN-18s when they are displaying a "1". I've replicated the problem. It has nothing to do with being multiplexed, or direct drive. It can occur in both drive modes. It has to do with stray currents, and current density. This anomaly can be reproduced by having all the "off" cathodes (0, 2-9) clamped at some voltage lower than ~90V. If you allow "off" cathodes to float higher than 90V, then it will not happen. Drivers like the 74141 clamp the cathodes to ~60V max, and allow it to happen. Here are some test results: <https://lh3.googleusercontent.com/-jqY6LzA8oOA/V2XLNlxrPII/AAAAAAAAYRw/7Xy2xOsHiBoqKo2kideH8GUhotJcTCkeQCLcB/s1600/Blue_Dot_Exp01.jpg> <https://lh3.googleusercontent.com/-jt6RuMyi4n8/V2XLZuAW-fI/AAAAAAAAYR4/F6ly8xJk1GM8rBm9G8Ieuq5hXyJiXZoFQCLcB/s1600/Blue_Dot_Exp02.jpg> <https://lh3.googleusercontent.com/-nSUHji1U1tU/V2XLuKkzBCI/AAAAAAAAYSM/UamA90DrbiA0YoGhGxfwrxgZvsDwNni3QCLcB/s1600/Blue_dot_exp3.gif> <https://lh3.googleusercontent.com/-U9_ZvafGi-w/V2XLlxvwMnI/AAAAAAAAYSA/GYDp_a5gfioPPkWccd_WrUVD0PRPeNEyQCLcB/s1600/Blue_Dot_Exp03.jpg> -- 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/2bf244c4-5314-4ff0-ae94-7226e41171bc%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
