Reverse Bias Blocks - Electronic Circuits Step by Step

Reversing the diode orientation blocks the branch in this ideal model. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Forward bias conducts in this model

With the diode direction aligned to the source, the branch carries 2 amperes.

I_{\text{forward}} = 2\ \text{A}

Reverse bias removes the conducting path

Flip only the diode orientation. The same source and limiter no longer form a conducting branch through the diode.

\text{reverse bias} \Rightarrow \text{blocked branch}

The reverse current is zero

The reverse-biased ideal diode gives a branch current of 0 amperes. No KVL loop is claimed through the reversed diode.

I_{\text{reverse}} = 0\ \text{A}

Blocked stays blocked across source sizes

The reverse-biased branch remains nonconducting for these exact training source values. The diagram shows the middle row.

\begin{array}{c|c|c|c|c}V_s&V_f&R&V_R&I\\6\ \text{V}&2\ \text{V}&5\ \text{ohm}&0\ \text{V}&0\ \text{A}\\12\ \text{V}&2\ \text{V}&5\ \text{ohm}&0\ \text{V}&0\ \text{A}\\18\ \text{V}&2\ \text{V}&5\ \text{ohm}&0\ \text{V}&0\ \text{A}\\\end{array}