Hi there!
I see you're eager to learn about electronics and are
also willing to invest some effort. Don't give up, keep
learning. You are at the beginning of a road that may
seem difficult in the beginning, but the rewards are
plentifull
Now, let's look at your problem.
The NE555 chip may be used to generate ~1s pulses, but they
are going to be determined by things such as R and C values,
which are not accurate (10-20% tolerance).
The frequency/accuracy will also depend
on temperature & supply voltage. In short, your 1 second pulses
will probably not be accurate. This may be important or not for you.
The proper way to get accurate 1s pulses is to use quartz crystal.
These are extremely stable and are used in such things as wrist
watches, telecommunications equipment etc.
You won't be able to find 1Hz quartz as this is not possible/practical
to manufacture, they are available at much higher frequenies, say
1MHz. What you do than is use divider chip to get it down to 1Hz.
Now, the thing with these divider chips (counters) is that they are
easier to implement in binary mode, meaning you get division
ration such as /2, /4, /8 ...... /1024, /2048....
This means that you also need a quartz with suitable frequency,
ie not 4.000 MHz, but rather 2.048MHz (/2048 gets you 1KHz precisely).
Fortunately these are plentifull for various typical frequencies.
What I recommend to you is that you use the 4060 chip, it is a binary
counter with oscillator which can also be made with quartz crystal.
I would suggest using the lowest frequency available quartz, which is
the 32768Khz (used in wrist watches). This way you'll get 2Hz out
of the 4060 (largest divide ratio is /16384).
http://www.mcamafia.de/nixie/images/nix_1hz.jpg
I've googled it up for you, you'll notice the additional divider by 2
to get it to 1Hz which is 1s pulse.
In fact, the whole page is interesting:
http://www.mcamafia.de/nixie/ncp_en/ncp.htm
Now you've got 1s pulses, but you still need to to power your display.
To do this you need decade counter, a counter which counts from 0
to 9. A good example would be 7490. The output of this counter will
be 4-bit decade code. Almost the same as binary, but only goes
up to 9 and then jumps back to 0.
You can't power display with this directly, so you need decade to
7- segment decoder, such as 7447. Here is the datasheet:
http://www.ee.washington.edu/stores/Dat ... 74ls47.pdf
And here is how to connect it:
http://travel.howstuffworks.com/digital-clock7.htm
This should help, too:
http://espresso.ps.admu.edu.ph/faculty/tris/display.gif
This is one good resource on theory about all this:
http://www.msoe.edu/eecs/ee/misc/100/logic_devices.doc
All this can also be done with one microcontroller.
http://chaokhun.kmitl.ac.th/~kswichit/clock/clock.htm
Its a small microprocessor with program memory and output pins
that can be directly used to control display.
As you see these make your devices much simpler and you can
program them to do anything you want so I really recommend these
to you. They open up a whole new universe for you and the initial steep
learning curve is well worth it.
Now I've given you some stuff to study so this should be a busy
weekend for you
Come back with questions when you've processed all that
And check our new schematics section, many ideas there also:
https://www.pcs-electronics.com/guides/new-schematics/
the crystal is a 32.768 khz crystal(??)....im going to use this circuit without the 4013 to clock a 4020 shift register and will use pin 6 to give me a pulse every minute for a repeating timer im building.....useful things these shift registers
