Way back when, I posted a winker circuit using standard eye tubes. These tubes usually have an internal triode, so making a simple (and low frequency; 1Hz-) phase shift oscillator is pretty straight forward:
http://www.dailymotion.com/video/x85oez_magic-eye-winker-eam86_tech A bit latter, Joe Sousa tried it with some DM160 tubes. These are somewhat a different animal, since they can be considered a single segment VFD. The triode here is not intended for amplification, but simply to adjust current, which adjust the brightness. They have such low gain that Joe had to use several in order to get a lumped gain high enough to sustain oscillation. Well I recently happened to fall upon a few of these. The 6977, in particular, which is the same thing as a DM160, but with the US Industrial number (where as DM160 is the European commercial number). I managed to get one going only using 3 tubes: http://www.dailymotion.com/video/xf0v04_3-by-6977-dm160-magic-eye-winker_tech Boy, but what a pain ! I had to stick a pot on it to adjust the bias. And it will sustain oscillation, in only a very narrow bias range. Which means if the temperature changes ever so slighty, it will stall. This reminds me of some of the 'electronic labs' I had back in school. Some circuits would only barely work. The most infamous was the analog multiplier based on the logarithmic area of a PN junction. You'd tweak that circuit just at the right spot, and within a few seconds it would drift out. Instructors would often tell us that they exposed us to these circuits in order for us to appreciate a solid design, over a temperamental one. I think just just enjoyed watching us squirm. Surprisingly, the 3 tube winker has been running about 5 hours straight, without stalling. The room is air conditioned. My compliments to the maintenance people. -- 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.
