Hello,

Since you have stated it is a college project, I moved it to homework help.

A lot of information on counters can be found in the links of this page:
http://www.educypedia.be/electronics/digitacounters.htm

There are more digital subjects over there too:

Digital electronics:
Arithmetic circuits D/A-A/D converters Number systems Codes and decoders Flip flops Technology Counters and registers General overview Technology-CMOS Digital logic Memories Technology-TTL Timers and oscillators

Can you show us what you have reached upto now?
That way we can see where you got stuck.

Bertus

 

Again, unless you want this to take up a ½ a meter or so square board space, you can get chips that are already mod6 and mod10 right off the shelf. If you really want to use individual flip flops that will work, it will just be bigger. Even with the mod6/mod10 chips it will still be pretty big. If you really want to go basic you could always use NOR or NAND gates, but I don't recommend it.

I'll be back, but it is bed time for me.

ok thanks...

 

can somebody tell me what is the connection on 7490??and the connections for the sec and 10 sec???

 

Your getting there, but the 7490 is a mod 10 (or mod5 and mod2) counter. For the digits that count to 6 you need a 7492, which is a mod12 (or mod6 and mod2) counter.

The 7447 will need resistors to drive the display LEDs, don't forget them.

What is the line power you have? In the USA it is 120VAC 60Hz.

I suspect the circuit will be a bit more complex for the 12 (or 24) counter. It appears you are aiming for a 12 hour counter. Some extra gates will be required to make it do what you need it to.

 

Bill,

The decade counters are fine. Using AND gates, the OP can reset the appropriate decade counters at the appropriate times.

 

The OP needs to decide which thread they want to work with, this one or
http://forum.allaboutcircuits.com/showthread.php?t=40451

One needs to be closed. We are duplicating efforts.