Yeah, after some development I've ended up using a completely different delay function that allows me to specify the amount of time on and off for the nixie. The minimum that works well is 50µs. It seems I miscalculated the time consumed by my last delay function. This also lets me set brightness from software and allows me to do fading effects very simply. However, I've run in to some cool things that probably won't end up actually being problems:
1.When the device is plugged in, even with the surge protector turned off, if I touch any of the neon lamps they light up a little bit (and if I touch them on the common cathode side, the other lamp lights up too). I feel no electrical sensation. This isn't really a concern, just cool. 2.I've been able to see this effect of the lamps changing characteristics depending on ambient light (ie how much they are pre- ionized). If I try to light up two lamps that share an anode, unless I have my desk lamp on, one of the lamps will fail to light for a second or so. I can actually control the activity of the lamps with a low- medium power (~15mW) blu-ray laser (high-energy 405nm photons). This could only end up being a concern if the same thing happens with the nixies and their comma indicators (which I intend to use). Also, I have a 1 megohm resistor between my base and emitter. Look at the bottom of page seven at http://nixietube.info/NixieTransistors.pdf for what I am using. A 10k resistor goes between the MPSA42 emitter and ground. I've been looking around craigslist for an old scope to buy, but nothing's really appealed to me. That new DSO quad digital mini-scope is actually really pretty nice (36ms/s) but I wish it was <$100 like its relatively mediocre counterparts. On Jan 22, 4:25 pm, threeneurons <[email protected]> wrote: > > On Jan 21, 3:58 pm, will <[email protected]> wrote: > > Yep, ... I needed to add what I believe was an extra 100 clock > > cycles (12.5us) or else the MPSA92s would stay partially on and > > allow just enough voltage to pass to cause an "off" bulb to flicker ... > > Now it's 100% contrast, no flickering at all. Very nice looking. > > 12.5uS is a tad on the quick side for nixies. You might want to add a > little margin and double, if not quadruple it. > I've used interdigit blanking intervals in the 50 to 200uS range, on > my nixie projects. But then, I could be a bit anal in that respect. I > haven't seen your anode drive circuit, but you should have a resistor > across from base to emitter on those MPSA92s. They should be in the > 10K to 22K range. They bleed off any charge across the base-emitter > junction, which looks like an open circuit, when the forward drop, > drops below 0.6V, and keeps MPSA92 ON a bit longer. > > A scope would be a good investment. There's been talk of cheap little > digital scopes, lately, but you can get good used analog scopes for > not much money. Shipping might be the biggest cost. Another thought is > to build your own analog scope with little 2" & 3" CRT tubes that pop > up on eBay often. You can use old scope manuals to find the schematics > as your guide. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. 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.
