Analog Intuition

Thevenin/Norton Equivalent Explorer

Deprecated. Early ADI wiki companion demos — unmaintained. A MIT 6.002-aligned Circuits & Electronics course is planned.

Thevenin & Norton Equivalents

Any linear two-terminal network looks identical to a voltage source in series with a resistor (Thevenin) or a current source in parallel with a resistor (Norton). Sweep the load and feel max power transfer at R_load = R_th.

Circuit Parameters

Source Voltage V_s (V)

Source Resistance R_s (Ω)

Load Resistance R_load (Ω)

Equivalent Values

V_th = V_oc • R_th = V_th / I_sc

V_th (open-circuit)

—

R_th

—

I_n (Norton)

—

R_n = R_th

—

I_n = V_th / R_th

Load Results (all three views agree)

V_load

—

I_load

—

Power in R_load

—

V_load, I_load, and P_load vs R_load

Red marker: current R_load. Green marker: R_load = R_th (maximum power transfer).

Why this matters

For the simple network V_s in series with R_s, the terminals are everything to the left of R_load. With the load removed (open circuit), no current flows and V_th = V_s. Short the terminals and I_sc = V_s / R_s, so R_th = R_s. Norton form is just the dual: I_n = V_th/R_th in parallel with R_n = R_th.

Power delivered to the load is P = V_load × I_load. It peaks when R_load = R_th — the classic maximum power transfer result. (Note: this is not the same as maximum efficiency, which favors a much larger R_load.)

Living demo for Chapter 1 — Introduction: circuit theory basics (sections 1.5–1.6).