THREE-STATE LOGIC GATE

What is a 3-state logic gate?
Three-state logic gate. Three-state gates feature three different output states: a low-level state (0), a high-level state (1), a high-impedance state, or a floating state (Z).

In this state, the output behaves as if it is not yet connected to the circuit, except for a small leakage current that can flow in or out of the output terminal. Output can have one of three states: logical 0, logical 1, and high impedance.

An output with three possible states is known as a three-state output or sometimes a tri-state output. Three-state devices have an extra input, which is generally called “Enable” or “Enable” to set the device’s outputs to the high impedance state.

three-state logic gate

A three-state bus, which is very common in computer or control equipment, is produced by connecting several triple-state outputs together.

buss 3 states

Devices with three-state outputs are normally designed so that they enable delay (from HI-Z to low or high) is slightly longer than the disable delay (low or high to HI-Z). This is because if a control circuit activates the output enable input of the first device, this ensures that the second device enters the high impedance state before the first device places a High or Low level on the bus.