Digital Logic Gates and the Clock

[LiquidOrb24]

Whenever I'm making a circuit in LogicWorks (or any other software used to make schematics) the input signal that goes into the circuit originates from a clock that has some sort of offset. I'm just wondering that if I wanted to make the circuit, what exactly is the clock? I have a bunch of logic gates such as NOR and NAND and I understand how the circuit works, but I just dont know what the clock is that I need. Do I have to make it, or is there a certain IC that I can buy that produces the clock signals.
I'm sorry I dont know if this makes sense to all of you or if you know what I'm talking about. But this is just driving me crazy because I cant build anything unless I know what this clock is and how I make it. Please help me.

Any help would be most appreciated. :x

 

[0mega]

555 timer sending square wave will work nicely for a regular inputb

 

[John Sorensen]

You can buy oscillators with CMOS or TTL outputs, and you can also get binary counters like the '4040 or '4020, which will let you divide it into lower frequencies. Or, like omega said, you can get a 555 and build a clock yourself, which will let you make arbitrary frequencies. Though, in general, a 555 will not generate Mhz clocks like an oscillator or crystal will.

j.

With an oscillator, all you need is +5 and grd, and you get a clock output.

 

[Dialtone]

I think what he wants to know pertains to clocking function. In that case, a clock is nothing more than a repeatative signal used to perform the logic operations in an orderly time interval sequence.
It is not necessary to have a clock signal in all instances, but having one (or several) helps sort things out in complex logic arrays where signal timing is more critical.
Dialtone