Digital Logic Tutorial

The 4 bit Register

Because binary digits (or bits) can be put together to represent any number, you can assemble several bits of memory (D flip-flops) to make a "Register" which holds any number up to some useful value. I this case, we are putting 4 together to make a "nibble" of memory, enough to hold one hexadecimal digit; 0-9 and A-F.

Notice that no matter what you do with the input, the output doesn't change until you press the button.

Next:

T-Flip Flop or Binary and Decimal Numbers

See also:

• http://2x-1.net/ob/gray1/ You can actually make an entire computer from memory... given enough of it. And it's best if some of the memory is preloaded with data: ROM (Read Only Memory) is memory that doesn't change, and retains it's values even after being powered off.