urgent.....digital clock....help pls!!!!

[frances]

i'm newbie here... hope all u guys can help me.....we were ask to build/design a digital clock that can be interchange from a normal 12hour clock to military time clock.... what will we do first? we were advice to use 7490 and 7492 ICs.... we have no idea to construct the diagram....... how will we start it......

pls help me!!!! thank you in advance!!!


godspeed everyone!!!!

 

[k7elp60]

Millitary time is 24 hour time. Midnight to 12 PM is the same. 1 PM normal time becomes 1300 hours, 2PM become 1400 hours and so forth.
Minutes and Seconds remain the same.
I am not aware of any current clock chips availible to make it easier to design a build a clock. You can start off with a time base of 1 pps, divide by 60 for seconds, divide by 60 for minutes, and then divide by 24 for hours.

 

[Styx]

Also they are normally referenced against "Zulu" hour or GMT

 

[gauri_22480]

help plzzzzz.......its urgent!!!!!!!

hiii
my 555 is not giving me output pulses(astable)......I have connected properly.....but osciloscope is not showing pulses........nothing is wrong in connections.......I have checked everything........what should I do...........plz help.........very urgent.........already waste so many days on this..............

 

[Nigel Goodwin]

Re: help plzzzzz.......its urgent!!!!!!!

hiii
my 555 is not giving me output pulses(astable)......I have connected properly.....but osciloscope is not showing pulses........nothing is wrong in connections.......I have checked everything........what should I do...........plz help.........very urgent.........already waste so many days on this..............

A 555 is a very simple and reliable circuit. If it doesn't work you've either got it wired wrong or you have a faulty component - assuming you're using this as a clock generator it's not going to be a very accurate clock though!.

 

[Optikon]

Re: help plzzzzz.......its urgent!!!!!!!

hiii
my 555 is not giving me output pulses(astable)......I have connected properly.....but osciloscope is not showing pulses........nothing is wrong in connections.......I have checked everything........what should I do...........plz help.........very urgent.........already waste so many days on this..............

check your circuit... don't assume anything. 99.9% chance it is wired wrong(loose connection etc..), If it is designed properly to begin with. :roll:

Can you post what you've wired?

 

[bimalchandran]

hiii
my 555 is not giving me output pulses(astable)......I have connected properly.....but osciloscope is not showing pulses........nothing is wrong in connections.......I have checked everything........what should I do...........plz help.........very urgent.........already waste so many days on this..............

check the connections again with polaritis of the capacitors,ic 555 never fails with other problems unles circuit failure.

 

[blueroomelectronics]

Check the date on the threads... This is almost 5 yrs old.

 

[JimB]

check the connections again with polaritis of the capacitors,ic 555 never fails with other problems unles circuit failure.

This thread is over four years old, the question you have just answered was asked by a"one post wonder" who has not been here for over four years.

JimB