Three-state output circuit is what does not mean to understand
High level low level vacant
There is nothing to pick up the sky
Three-state gate, tri-state circuit is an important bus interface circuit. The tri-state here means that its output can be either a normal "0" state and a "1" state of the general binary logic circuit, and can maintain a unique high-impedance state, a third state - a high-impedance state Gate circuit (high impedance state is equivalent to cut off state). In the high impedance state, its output is equivalent to the open state, there is no logic control function. The output logic state of the tri-state circuit is controlled by an input pin. When G is low input, the tri-state circuit exhibits a normal "0" or "1" output; when G is high, the tri-state circuit gives a high-impedance output.
Is a high level, low level and high impedance three output state of the gate circuit, also known as three-state gate output circuit. In the solid state machine board circuit, "I / O" board circuit, in addition to the above several combination of gate circuits, three-state gate circuit is also essential.
