Gates: Buffer

Buffer: implements equality function

Input: 1 bit

Symbol:

Output: 1 bit

Truth table:

Input

Output

x

z

0

0

1

1

This doesn't look very interesting at all!

There is a practical reason for it, however:

Circuits use electrical signals: 0 and 1 are represented by voltage.

If current is too low, it's hard to measure voltage accurately.

"Fan out" (number of devices) reduces

amount of current.

If the current from the AND gate is

distributed equally, then each

device gets 1/4 the current.

A buffer can be used to "boost" the current back to the right level:

The buffer (like all other gates) is an active device; it requires power input

to maintain current and voltage.

That's all EE stuff, and we're programmers.  Why should we care about that?