Launch Power Comes From Voltage Times Current - Electromagnetic Transmission Lines: Signal Propagation and Reflections Step by Step

Power is tied to the same source-bound 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

Power uses the same launched current

The current is still 3 amperes; it is not a separate caption.

I_{+}=3\ \text{A}

Launched power is voltage times current

The launched power is 12 volts times 3 amperes, or 36 watts.

P_{+}=12\cdot 3=36\ \text{W}