Series Circuit Calculator Formula

Understand the math behind the series circuit calculator. Each variable explained with a worked example.

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Formulas Used

Total Resistance

total_resistance = r_total

Circuit Current

current_flow = circuit_current

Voltage across R1

v_r1 = circuit_current * r1

Voltage across R2

v_r2 = circuit_current * r2

Voltage across R3

v_r3 = circuit_current * r3

Variables

VariableDescriptionDefault
v_supplySupply Voltage(V)12
r1Resistor R1(Ω)100
r2Resistor R2(Ω)200
r3Resistor R3 (0 to skip)(Ω)300
r_totalDerived value= r1 + r2 + r3calculated
circuit_currentDerived value= v_supply / r_totalcalculated

How It Works

Series Circuit Analysis

In a series circuit every component carries the same current. Resistances add directly.

Formulas

R_total = R1 + R2 + R3

I = V / R_total

V_Rn = I x Rn

The sum of all voltage drops equals the supply voltage (Kirchhoff's Voltage Law).

Worked Example

12 V supply with 100, 200, 300 ohm resistors in series.

v_supply = 12r1 = 100r2 = 200r3 = 300
  1. 01R_total = 100 + 200 + 300 = 600 ohms
  2. 02I = 12 / 600 = 0.02 A
  3. 03V_R1 = 0.02 x 100 = 2.0 V
  4. 04V_R2 = 0.02 x 200 = 4.0 V
  5. 05V_R3 = 0.02 x 300 = 6.0 V
  6. 06Check: 2 + 4 + 6 = 12 V

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