← back to legend
Physical / electrical concepts

High-impedance / Hi-Z

An output state where the pin is neither driving high nor low, effectively disconnected from the circuit.

How it looks

Drawing
THREE STATES OF ONE OUTPUTHIGHLOWHi-Z: both off
In Hi-Z the pin is as good as unplugged.

How it works

TWO CHIPS SHARING ONE WIREshared wirechip Achip BtalksHi-ZHi-ZtalksHi-ZHi-Znobody drives: a pull-up or pull-down decides

Where it fits

Hi-Z is the third state of a push-pull output (both switches off). The danger it avoids is bus contention / collision.

← back to legend