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Maximum power transfer

Network analysis · Advanced · about 20 minutes · part of Zen’s Electronics Design Mastery

A source with internal resistance R_s delivers the most power to a load when R_L = R_s. At that point only half the power reaches the load.

Maximum power transfer: the circuit on the simulator's bench

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How it works

PL = Vs² · RL / (Rs + RL)² = 32 mW at RL = 2 kΩ

Maximum at RL = Rs = 1 kΩ: Pmax = Vs² / 4Rs = 36 mW, with 50 % efficiency.

Try it on the bench

  1. Scroll over the R_L pot slowly from 0 % upward and watch P_L rise, peak and fall.
  2. The best R_L lands on 1 kΩ, equal to R_s.

Parts on the bench

In the course

Zen’s Electronics Design Mastery, module “DC Circuit Analysis”.

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