Logic level

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In digital circuits, a logic level is a particular state that a particular signal can have. Logic levels are usually represented by the voltage difference between the signal and a common reference point (usually ground), however other standards exist. The exact range of voltage level that represent each state depends on the particular technology being used (see Digital logic#Logic voltage levels).

The two most common logic levels are logical high and logical low, which generally correspond to a binary 1 and 0 respectively (however, see Active low). Signals with one of these two levels can be used in boolean logic for digital circuit design or analysis.

In three-state logic, a signal can also be high impedance, which means it is not actively asserting either a high or a low logic level.

[edit] See also

• Boolean logic
• Three-state logic
• Four valued logic
• High impedance