Logic gates are of the lowest digital abstraction level which operates on 0s and 1s. (source for ref.: https://bjc.edc.org/bjc-r/cur/programming/6-computers/1-abstraction/01-abstraction.html).
Network (digital circuit) created out of logic gates is called Register-transfer Level (RTL). As it is created out of gates, it is also considered gate level. (no ref. source)
Automata is akin to a robot, i.e. a self-operating mechanism. (no ref. source)
|Combinational Circuit||Sequential Circuit|
|No output feedback to input||Has output feedback to input|
|Multiplexer and Encoder||Registers and Flip-flops|