• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

1hz for a clock thing im building

Not open for further replies.


New Member
i looking for a way to get a clock pulse using +5v of 1hz i dont know if i can use the 555 timer chip i have to get it, or if i sould use a higher frequency and use the decade counters i have to do a divide-by-ten till i get what i need, or if im doing everything worng and there is an easier way. Its all for some 7-segment displays i want to build into a clock for my computer and i just need the decade cunter chip to count up each second

thank in advance,


A 555 may not be accurate enough. You can divide your mains voltage by 50 (or 60 in the USA) for 1 Hz.


Active Member

I always keep the quartz units from broken or damaged
clocks. They give a one second pulse, they are only
small and they are very, very accurate.

Even if you have to buy one they are cheap, and easier
than trying to get one second intervals by dividing
down the main supply or by dividing down from a crystal.

They are mostly one and a half volt working, but thats
not a problem as they are made to be very low current.

The R-C system is not accurate enough for a clock, as
any error is cumulative.

You want to build a clock for your computer ?

Your computer has no clock ?
You will need more than a decade counter to run a clock
from a one second pulse.

There are plenty of chip circuits about to give you the
appropriate divisions,
unless you want your PC to do the work and output the
drives to the seven segment displays ...

Is this some kind of project or homework exercise to
make a computer program drive seven segment displays ?

A clock made like that would stop when you turn off
your computer.

Best of luck with it,
John :)


New Member
cool thanks, i'll grab some of the quartz

what i ment with the first counter is after i have one and a decoder to get the 7 segment display working i can carry after i get to 9 to the next counter without a problem. i just need to get one working first.

im trying to use some chips that when they count can stop and store the data with low voltage so i could run it off a battery. i want somthing that will show the total time my system has been on. there lots more stuff i have to realise is wrong before i get it done but its just an extra mod project to customize my new comp

All in all i hope that i can have 8 7-segment displays that begin counting when my computer is powered on (i'll connect one of my molex connectors) and keep counting untill the primary power is off. then store the data untill the next time my comp is powered on i'll have 2 displays for the seconds, 2 for the minutes, and 4 for the hours. It ends up being about 416 days of ON time before i would reset it and proly buy a new comp by then anyway.

thanks again


Active Member

i have a feeling that Win98se has an 'Hours run' counter
buried in there somewhere.
i vaguely recall seeing it, or something similar.
but i may be mistaken.

I will have a quick look through msinfo32 just in case
i spot it.

Maybe someone else knows for sure.

Regards, John :)


New Member
do a google for xteq x-setup or tweakUI. They are utilities with loads of features, and both include a system uptime.

Or You could just do the following:

See How Long Windows Has Been Running

Click the "Start" button, choose "Programs," then "Accessories," then
"System Tools," and select "System Information." On the window that
appears, look at the right pane next to "Uptime." This will tell you how
many days, hours, minutes, and seconds Win98 has been running
since the last restart


Active Member
Hi craigey1,

yes, i found that one, but what about a total run time ?
I couldn't see it in tweakui.

I still think i have seen it somewhere in there.



New Member
hey thanks guy that stuff is cool

but i still wana see if i can avoid using software for it, just a way to turn it on, keep the data when its off, show the numbers, and reset it when i get my new comp
Not open for further replies.

Latest threads

EE World Online Articles