Bridge Threshold Margin Audit - Electronic Circuits II Step by Step

A bridge-driven decision follows the computed divider-node difference and a strict threshold comparison. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

A bridge decision starts with two divider nodes

The bridge voltage is the absolute difference between the left divider output and the right divider output.

V_{\text{bridge}}=\left|V_{\text{left}}-V_{\text{right}}\right|

Right-branch changes grow the bridge voltage

The left divider is fixed. The right bottom resistor changes the right divider output, so the bridge voltage grows by exact rows.

\begin{array}{c|c|c}V_{\text{left}}&V_{\text{right}}&V_{\text{bridge}}\\8\ \text{V}&8\ \text{V}&0\ \text{V}\\8\ \text{V}&\tfrac{36}{5}\ \text{V}&\tfrac{4}{5}\ \text{V}\\8\ \text{V}&6\ \text{V}&2\ \text{V}\\\end{array}

A strict threshold turns only after the bridge is large enough

The threshold comparison is strict. Equal or smaller measured values do not close the ideal threshold switch.

\begin{array}{c|c|c}V_{\text{bridge}}&V_{\text{threshold}}&\text{decision}\\0\ \text{V}&1\ \text{V}&LOW\\\tfrac{4}{5}\ \text{V}&1\ \text{V}&LOW\\2\ \text{V}&1\ \text{V}&HIGH\\\end{array}

The rendered bridge row remains below threshold

For the rendered bridge, the measured difference is below the threshold. The strict above-threshold decision is therefore low.

\tfrac{4}{5}\ \text{V}<1\ \text{V}

Bridge margins come from computed node differences

A bridge decision should cite the two divider outputs, the bridge difference, and then the strict threshold comparison. The final row is high only because the computed difference exceeds the threshold.

V_{\text{bridge}}>V_{\text{threshold}}\Rightarrow \text{HIGH}