An ideal threshold switch follows the computed bridge voltage, not a hand-authored label. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Use the computed bridge voltage

The unbalanced bridge gives 2 volts.

Vbridge=2 VV_{\text{bridge}} = 2\ \text{V}
Bridge measurementThe bridge voltage is computed from two dividers.12 V3 ohm6 ohm4 ohm4 ohmV2 V+-4 V+-8 V+-6 V+-6 Vbridge

The threshold decision follows the voltage

The bridge voltage is above the 1 volt threshold, so the ideal switch state is derived as on. Noise margins, hysteresis, and propagation delay are deferred.

2 V>1 V2\ \text{V} > 1\ \text{V}
Bridge drives a decisionThe lamp state follows the exact threshold comparison.closedlampaboveon