Logic Levels

Threshold Classifies Input

exact boundary rules

A logic input is accepted only after exact voltage thresholds classify it. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Equality at the low threshold is LOW

An input of 1 volt equals the low threshold, so the helper classifies it as LOW.

1 V≤1 V⇒LOW1\ \text{V} \le 1\ \text{V}\Rightarrow \text{LOW}
Low thresholdEquality at the low threshold is accepted as LOW.V1 VV1 VV4 VinputLOWHIGHLOW

Equality at the high threshold is HIGH

An input of 4 volts equals the high threshold, so the helper classifies it as HIGH.

4 V≥4 V⇒HIGH4\ \text{V} \ge 4\ \text{V}\Rightarrow \text{HIGH}
High thresholdEquality at the high threshold is accepted as HIGH.V4 VV1 VV4 VinputLOWHIGHHIGH