Equal Inputs Tie Rule - Electronic Circuits III: Comparators and Interfaces Step by Step

The equality case is explicit so the comparator output is never a caption guess. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Equal inputs trigger the declared tie rule

Both comparator inputs are 6 volts.

6\ \text{V} = 6\ \text{V}

This book ties equality to the low rail

The declared tie rule selects the low rail, so the output is 0 volts.

V_{\text{out}} = 0\ \text{V}