What are the defining characteristics which make Buffer-driver and Buffer-gate separate ?

Question

What are the defining characteristics which make Buffer-driver and Buffer-gate separate ?

Answer 1

Both types provide an output that is capable of driving many tens of milliamps of current into the load.

A buffer-driver has a single input and a single output.

A buffer-gate has a single output, but it has more than one input which affects the output.  The gate may be a logic function, or one input may be an enable for the output which controls the state (tri-state, invert-the-input, follow-the-input).

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