Ahh, I agree with David on this one. Lucky. I have been working with this stuff since around 1990, and during that time have only ever found a small bunch of (10) of those 74142 ics. They are extremely rare, made of pure unobtainium!
They are the equivalent of a decade counter connected to a 74141 and all in one 16-pin DIP package. TTL cookbook page 93 describes it. Some notes from last time I had mine fired up: Counter clear pin 1 is very sensitive to noise. If using a 2.2k pullup resistor, a .01 uf or a .1 uF to gnd. keeps the full count going. Without the cap, the count goes 0 1 2 3 4 5 0 Carry out pin 14 stays high for all counts except 8 and 9. Carry is low for counts 8 and 9, and it returns high when count 0 is reached. 74142 belongs in a glass case, temperature and humidity controlled, low light, nitrogen atmosphere. Chuck > > >---- Original Message ---- >From: [email protected] >To: [email protected] >Subject: Re: [neonixie-l] Question on SN74142s >Date: Thu, 23 Feb 2012 21:15:54 -0800 > >>They're also covered in the TTL Cookbook (That's where I found out >about >>them)... Where did you find them?!? >> >>-Adam >> >>On Thu, Feb 23, 2012 at 6:44 PM, David Forbes ><[email protected]> wrote: >> >>> On 2/23/12 7:11 PM, Dylan Distasio wrote: >>> >>>> Hi all- >>>> >>>> I recently picked up 2 SN74142 ICs. I'm about to show my >ignorance >>>> again, but can someone with some patience walk me through how I >would >>>> use these in a nixie clock. I'm familiar with the 74141s but >have to >>>> admit after reading the SN74142 datasheet I am not entirely sure >how >>>> this one works. I am still a beginner at digital logic, and >would >>>> appreciate any help with utlizing a combo of a decimal counter / >4-bit >>>> latch /decimal decoder/ nixie driver in one IC. >>>> Datasheet http://diogenes.iwt.uni-**bremen.de/vt/laser/nixie/** >>>> >SN74142.pdf<http://diogenes.iwt.uni-bremen.de/vt/laser/nixie/SN74142. >pdf> >>>> Best, >>>> Dylan >>>> >>>> >>> Dylan, >>> >>> Lucky man! I've never seen one of those chips in person. >>> >>> I have used the old CMOS more-or-less equivalent, the CD4033 >(which drives >>> 7-segment LEDs) to make a clock. You will need to wire the latch >in >>> transparent mode, as the latch function is not needed for a clock. >>> >>> RCA published an app note in their 1974 data book that I built in >1976. It >>> worked. I'll see if my scanner will cooperate enough to scan the >app note. >>> >>> -- >>> David Forbes, Tucson AZ >>> >>> >>> -- >>> 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 >neonixie-l+unsubscribe@** >>> googlegroups.com <neonixie-l%[email protected]>. >>> For more options, visit this group at http://groups.google.com/** >>> >group/neonixie-l?hl=en-GB<http://groups.google.com/group/neonixie-l?h >l=en-GB> >>> . >>> >>> >> >>-- >>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. >> >> $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 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.
