If you want to light up a neon bulb, with that chip, add an extra 220K resistor. Hook it up in parallel with the neon bulb. That should keep any leakage current, when off, from hitting a level to fire the neon.
On Saturday, April 18, 2015 at 9:55:02 AM UTC-7, Chaos Hydra wrote: > > Thanks John! That is very helpful! > So to avoid unwanted lit, what should I do? Can I just put a diode there > to prevent the chip sourcing the bulb? > > > On Saturday, April 18, 2015 at 10:13:40 AM UTC-4, jrehwin wrote: >> >> >> On Apr 18, 2015, at 4:06 AM, Chaos Hydra <[email protected]> wrote: >> >> > Hello! First time post here. So I am doing a nixie clock with IN-12 and >> KM155ID1 mux chip. >> >> The KM155ID1 is a nixie driver, not really a "mux chip", although it can >> certainly be used in multiplex designs. >> >> > To ensure the look, I decided to use INS-1 neon bulb to do the little >> colons between the digits. My questions is: can I drive the INS-1 bulb as I >> did to IN-12? With an 220k current limiting resistor under 170VDC, the INS >> bulb got 5mA. Considering IN-12 has 6mA without current limiting resistor, >> I think I can just use K155ID1 to sink in the current and control the neon >> bulbs. >> >> Yes, the chip won't mind at all. However, due to the clamp diodes, the >> "off" voltage is about 100V (60V for the US equivalent). With an ordinary >> nixie this is fine as long as another cathode is lit. However, >> for individual bulbs and nixies without any cathodes lit, that's enough >> voltage across the tube to possibly cause some unwanted glow. >> >> > Consider I give most of my knowledge of digital parts' parameter back >> to professors, can any one please point out on the data sheet: when I am >> sinking current into the active low pin(to turn on an bulb or a single >> filament in nixie), which value is the maximum current? >> >> That does not appear to be given on the data sheet, however, it does say >> that when sinking 7mA, the voltage on an output pin will not exceed 2.5V, >> so 7mA is allowed by implication. >> >> - John >> >> -- 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/40811843-8a9c-4aee-90cf-9de637860703%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
