hello!
Am trying to making a clock using a 74Ls192 counter, a 7447 decoder and 7 segment display. im experimenting one but it doesnt work! anyone who can help with a circuit with these requirements?? thanks

 

That's a good place to start learning about TTL. Do it in stages.
Get the breadboard, 5V power source and make 1Hz clock signal
(to start with experimenting, you can use 555 chip or whatever).
The stuff you learn by experimenting is great basis for future projects
so don't hesitate.Download datasheets for your chips (just search the web using Google
or whatever you like). They often show sample diagrams.
Your counter chip is presetable so try to use this feature.
For example, put dip switches from +5V to preset inputs and resistors
from preset inputs to 0V. When you pull pin 11 down (load input
ius inverted what can be seen by line over word LOAD) the binary
combination that is at the preset inputs is loaded to counter.
LOAD input can be momentary button wired from pin 11 to 0V (GND)
and maybe a pullup resistor (1k from pin 11 to +5V for example).
You should see the same state on the outputs so when you bring the
clock signal to the inputs UP or DOWN, counter will count from this
number. Clear (CLR) does the same job but it always loads value 0
(resets all outputs). Note that CLR input is not inverted (no line
over CLR signal name). This means to issue CLR signal, you have to
bring "1" to pin14 and to issue LOAD you have bring "0" to pin11.
And don't forget to bring counter ouputs (pins 7,6,2 and 3 of your
counter should go to pins 6,2,1 and 7 of decoder chip)
to inputs of the decoder chip. Make sure that decoder is enabled
and display is not blanked so you can see your circuit counting.
To do so, you have to pull some of the 7447 inputs high or low.
The easiest way to find out how this works is like described - use
dipswitches and pull down (or pullup) resistors so you can toggle
the state of inputs like LT, RBI etc.

Happy experimenting...

 

Don't waste your time with TTL, start lerning about CMOS, is better than TTL, easier to use, faster in HC version, low power, and so on...

 

who cares if it is TTL or cmos, just do it!

Note: although i would recommend TTL over CMOS purely because they are so annoying when you turn the circuit on only to find out that they have been fried thanks to static electricity...that is a trade off for low power though.

__________________
www.winpicprog.co.uk - Great PIC language tutorials.

 

40-series CMOS are very well protected against static electricity. In fact, I dont give them any special treatment and yet I never had a defective one due to static electricity ...

I'm not saying it can't happen, just that is rare...

 

I agree...

 

Hi there,
I think I can help U with the 7 segments display
here R 2 pdfs which may help U
I found them on the net

Attached Files

	7segdisplay_imp_.pdf (176.3 KB, 34 views)
	7447.pdf (67.4 KB, 24 views)

 

url's of download are not working. tried 2 times but alas!!
aurosunil

 

url's of download are not working. tried 2 times but alas!!
aurosunil

 

those are common parts. just google for datasheets...

 

Hello there!

Im trying to make the clock count down using minutes and seconds but it seems there something wrong with the circuit. Im using 4 74Ls192, 4 7447 decoder and 7 segment display. I connected the pin 4 to pin 13 of the 192 and the pin 4 of the last 74192 to the clock. The minute counter would show up to 15 and not 9. Also, how can I stop the clock if i set the minute to a value.

Thanks