How do Norton equivalents relate to Thevenin equivalents?

• A. True
• B. False
• C. Yes; but only for linear circuits
• D. Yes; only when dependent sources present

Answer: (C)

The idea being tested is that Norton and Thevenin representations describe the same external behavior of a circuit from the viewpoint of its terminals. For any linear, bilateral network, you can replace the interior with either a Thevenin equivalent—a voltage source in series with a resistor—or a Norton equivalent—a current source in parallel with a resistor—and the load will experience the same voltage and current for any connection. The link between them is straightforward: In = Vth / Rth (and Rth = Rn, with Vth = In × Rth). This relationship holds even when dependent sources are present, as long as the overall network is linear. If the circuit is nonlinear, a single fixed Thevenin or Norton equivalent generally can’t represent its behavior for all loads, so the simple conversion isn’t valid. That’s why the correct idea is that Norton equivalents relate to Thevenin equivalents for linear circuits only.