Thevenin Equivalent Calculator Formula

Understand the math behind the thevenin equivalent calculator. Each variable explained with a worked example.

Formulas Used

Thevenin Voltage

v_th = v_source * r2 / (r1 + r2)

Thevenin Resistance

r_th = r1 * r2 / (r1 + r2)

Variables

VariableDescriptionDefault
v_sourceSource Voltage(V)24
r1Series Resistance R1(Ω)1000
r2Load-side Resistance R2(Ω)2000

How It Works

Thevenin's Theorem

Any linear circuit can be replaced by V_th in series with R_th.

Formulas

V_th = V_s x R2 / (R1 + R2)

R_th = R1 || R2 = R1 x R2 / (R1 + R2)

Worked Example

24 V source, R1 = 1k, R2 = 2k.

v_source = 24r1 = 1000r2 = 2000
  1. 01V_th = 24 x 2000 / 3000 = 16.0 V
  2. 02R_th = 1000 x 2000 / 3000 = 666.67 ohms

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