MPS A42. NPN. Used 15 per board to make driver cards for each B-7971 tube, in a 16-tube array here.
Each of those driver boards has those 15 transistors being operated by the outputs of (2) 74LS273 ics. Those ics store the segment pattern to light the tube segments in any order, in any pattern. Then, using the parallel-load data pins on those ics, commoned up to a 15-bit bus, and then strobing the appropriate tube's set of 'LS 273s, via the "load" pin, digits or characters can be put up on the tubes at will. Soldering down 15 transistors per card, and making 16 cards was fun, and it was done while watching lots of Howard Stern on TV, back when he was on *plain old antenna* TV. The cards are 4 inch square Radio Shack 276-154A, and they have the handy-dandy 22/44 edge connector. That so far is my favorite tube-driver project. I made two little custom card cages holding 8 cards each, to house these. Then, the entire scrolling circuit and storage of large blocks of text was done with another several bucket loads of TTL and an old ASCII keyboard, and a non-volatile SRAM to hold the data to be scrolled. Chuck > > >---- Original Message ---- >From: [email protected] >To: [email protected] >Subject: Re: [neonixie-l] Favourite chips... >Date: Mon, 05 May 2014 12:03:19 -0700 > >>On 5/5/14 11:49 AM, Nick wrote: >>> On Monday, 5 May 2014 18:04:34 UTC+1, nixiebunny wrote: >>> >>> For individual transistors, the SOT-23 MMBTA92 is commonly >used >>> >>> >>> Do you mean MMBTA42 - the '92 is PNP - most folk I know of use the >'42 (NPN) >>> >>> Nick >>> >> >>Of course. Silly me. The '92 is a PNP anode driver transistor. >>If I used them more often, I'd get those numbers straight. >> >> >>-- >>David Forbes, Tucson AZ >> >>-- >>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/5367E077.9050103%40dakot >acom.net. >>For more options, visit https://groups.google.com/d/optout. >> $4.95/mo. National Dialup, Anti-Spam, Anti-Virus, 5mb personal web space. 5x faster dialup for only $9.95/mo. No contracts, No fees, No Kidding! See http://www.All2Easy.net for more details! -- 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/380-22014515193114684%40all2easy.net. For more options, visit https://groups.google.com/d/optout.
