Digital Circuits
From Mech
Terminology
Active Low Input
An active low input means that it is "on" when in input is low, and "off" when the input is high. In schematic diagrams, it is often denoted by a "bubble" at the input pin.
High
High usually corresponds to the binary "1", the "on" state, and "true" or "1" in Boolean logic.
Low
Low usually corresponds to the binary "0", the "off" sate, and "false" or "0" in Boolean logic.