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| Electronic Projects Design/Ideas/Reviews Are you building an electronic project or want to? Maybe you need some assistance? Come and submit your electronic questions here and let our experienced members find a solution. |
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3rd November 2007, 02:09 PM
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Experienced Member
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Just download the IC datasheets for the pin diagrams. Prefix SN to make the google search easier. SN7492, SN7447 etc...
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3rd November 2007, 06:03 PM
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Quote:
 Mine was a ton of work, but is really cool. The attachments are the pictures of it. (wrong Computer profile, cant access my pictures )
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MechTronics Last edited by Krumlink; 3rd November 2007 at 06:21 PM. |
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3rd November 2007, 11:48 PM
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Experienced Member
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zhdsdf
Try to Google for data sheets, most of these are standard TTL IC's, otherwise try to get hold of the TTL Cookbook from Don Lancaster. Cheers, Raymond
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There are more ways to get to Rome. Electricity, Electric clocks, Meters and Trains are great. |
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4th November 2007, 07:00 PM
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thanks
hi.
thanks for your answer.but I relinquished them.anymore it isn't my project. |
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4th November 2007, 07:25 PM
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aw, you would have had fun with it like my clock
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MechTronics |
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5th November 2007, 03:32 AM
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Experienced Member
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Ok here are some photo's of the diagrammes to make it easier for our members who can not find these TTL IC details.
This info is from my TTL Cookbook which i bought years and years ago, but occasionally these are for sale on Ebay. Info for the 7400, 7408, 7447, 7490, 7492 and 74160 attached. There are very good PDF files on the internet available as long the LS or SN is put in the search engine ( 74LSxx ) or ( SN 74xx ) Hope this wil help, Regards, Raymond edited to improve picture details
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There are more ways to get to Rome. Electricity, Electric clocks, Meters and Trains are great. Last edited by RODALCO; 5th November 2007 at 04:22 AM. |
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6th November 2007, 02:04 AM
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Experienced Member
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I've got those somewhere, Don Lancasters books were great.
http://www.tinaja.com/ |
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6th November 2007, 04:01 AM
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New Member
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thanks for reply.............
i think now i will be able to solve my problem....... thanks to alll |
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29th November 2007, 05:31 AM
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New Member
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hello guys...im a newbie here...
i need ur help, i've been making my own digital clock using this diagram...  i already connected the minute and second digits and its working, but the problem is that it doesnt start at 00:00 rather 15:14...pls help me guys... and if anyone knows how to add a set and reset button... i appreciate ur help guys, thnx in advance... and BTW, ive also tried the schema posted by rodalco but i can't understand the labels on the 7490...if its R0(1),R0(2),R90,R91...  i'd appreciate it if anyone can post a much more detailed schematic... thnx guys...  |
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29th November 2007, 06:44 AM
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New Member
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I am not trying to discourage you, but actually its a clock, then you don't need to have the clock at 00:00 everytime you turn it on, since you already have fast and slow counter to set your clock.
Take a look at the 7490 datasheet for pinout here: http://www.ee.washington.edu/stores/DataSheets/74ls/ cmiiw, to reset the Decade Counter, MR1 and MR2 pin set to Hi. Then it will give Lo output to Q0-Q3 which will make the 7447 set the 7segment to display 0. But it looks like your 10th hour can only display '1' and blank, not '0' and '1'. good luck! |
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21st February 2008, 04:43 AM
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New Member
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how to with 555
i am trying to build a digital clock without seconds. so i need to use a 555 to generate 60 hz and connect it to 7493 for minutes. but i could not design it. could any body help me pls.. thanks
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21st February 2008, 05:01 AM
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Experienced Member
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It'll be very inaccurate as the 555 is not a good timebase. The CD4060 can handle a crystal which might make it better suited.
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21st February 2008, 05:59 PM
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Experienced Member
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ibriazici Just build the clock with the two 7490 IC's for the seconds but don't attach 7447 ic's and 7 segment displays to them.
A 555 is not accurate via a timeing cap as already said by blueroomelectronics. zajioftheasuka, To get your clock to start at 00:00 you need to reset at all the R0 and R9 gates of the 7490 IC's.
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There are more ways to get to Rome. Electricity, Electric clocks, Meters and Trains are great. |
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15th March 2008, 09:17 AM
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Experienced Member
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The circuit drawn is all with 7490 IC's, because these are easier to get, it may be why your circuit doesn't work.
A 7492 is a 2, 6 and 12 divider. The clock schema is different if you built it with these IC's and you don't need the 7400 gates to divide out the 6. I see if I can find a 60 counter with those ic's.
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There are more ways to get to Rome. Electricity, Electric clocks, Meters and Trains are great. |
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15th March 2008, 02:33 PM
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Experienced Member
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see howstuffworks.com. search
'How digital clocks work' (its heavy n ive got a dial up connection). they have got a digital clock made with 7490. mod6 and mod10 u name it. with out the use of any gating circuitry.
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i would explain it to you but it would make your brain explode! 
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