load-power-is-output-voltage-times-current - Electronic Circuits XIII: Power, Rectification, and Regulation Step by Step

Regulated load power is computed from voltage and current. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Load power uses the regulated output

The headroom gate has passed, so the load power may use the regulated 5 V output and the declared load current.

P_{\text{load}}=V_{\text{out}}I_{\text{load}}

Load power follows current at fixed output voltage

The output voltage stays fixed. Each added current row raises load power by the same voltage scale.

\begin{array}{c|c|c}V_{\text{out}}&I_{\text{load}}&P_{\text{load}}\\5\ \text{V}&1\ \text{A}&5\ \text{W}\\5\ \text{V}&2\ \text{A}&10\ \text{W}\\5\ \text{V}&3\ \text{A}&15\ \text{W}\\\end{array}

Load power is output voltage times load current

The regulated load claim uses the checked output voltage and the declared load current.

5\ \text{V}\cdot2\ \text{A}=10\ \text{W}