Series Circuit Calculator Formula
Understand the math behind the series circuit calculator. Each variable explained with a worked example.
Formulas Used
Total Resistance
total_resistance = r_totalCircuit Current
current_flow = circuit_currentVoltage across R1
v_r1 = circuit_current * r1Voltage across R2
v_r2 = circuit_current * r2Voltage across R3
v_r3 = circuit_current * r3Variables
| Variable | Description | Default |
|---|---|---|
v_supply | Supply Voltage(V) | 12 |
r1 | Resistor R1(Ω) | 100 |
r2 | Resistor R2(Ω) | 200 |
r3 | Resistor R3 (0 to skip)(Ω) | 300 |
r_total | Derived value= r1 + r2 + r3 | calculated |
circuit_current | Derived value= v_supply / r_total | calculated |
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.
- 01R_total = 100 + 200 + 300 = 600 ohms
- 02I = 12 / 600 = 0.02 A
- 03V_R1 = 0.02 x 100 = 2.0 V
- 04V_R2 = 0.02 x 200 = 4.0 V
- 05V_R3 = 0.02 x 300 = 6.0 V
- 06Check: 2 + 4 + 6 = 12 V
Frequently Asked Questions
What happens if one resistor fails open?
The entire circuit breaks and no current flows.
Does resistor order matter?
No. Total resistance and current are the same regardless of order.
How do I handle more than three resistors?
Set R3 to 0 if unused. For more, add values together and enter the sum.
Learn More
Guide
Ohm's Law Guide
A complete guide to Ohm's Law. Learn the relationship between voltage, current, and resistance, with practical examples, the power triangle, and circuit analysis tips.
Ready to run the numbers?
Open Series Circuit Calculator