Formula used
Series resistance: Rₜ = R₁ + R₂ + … + Rₙ Parallel resistance: 1/Rₜ = 1/R₁ + 1/R₂ + … + 1/Rₙ Ohm’s law: V = IR Power: P = VI = I²R = V²/R Modified nodal analysis: Gv + Biᵥ = j Bᵀv = e Thevenin and Norton: Iₙ = Vₜₕ / Rₜₕ Rₙ = Rₜₕ Maximum power transfer: Rₗ = Rₜₕ Pmax = Vₜₕ² / (4Rₜₕ)
How to use this calculator
Select the network mode that matches your circuit. Add every resistor and source with accurate node labels. Use zero for the reference ground node.
Choose output terminals for equivalent and Thevenin calculations. Add tolerance, power, voltage, and thermal ratings. Then press Calculate network to solve everything.
Review node voltages, currents, power, temperature, and warnings. Export results using CSV, JSON, SVG, or browser PDF. Confirm component ratings before building hardware.
Example data
| Component | Type | Value | From node | To node | Purpose |
|---|---|---|---|---|---|
| V1 | Voltage source | 12 V | 1 | 0 | Supplies the network |
| R1 | Resistor | 1 kΩ | 1 | 2 | Upper divider resistor |
| R2 | Resistor | 2.2 kΩ | 2 | 0 | Lower divider resistor |
| R3 | Resistor | 4.7 kΩ | 1 | 0 | Parallel source load |
Frequently asked questions
What does equivalent resistance mean?
Equivalent resistance is the single resistance seen between selected terminals. It produces the same terminal current for a test voltage.
Can this calculator solve bridge circuits?
Yes. Enter each bridge resistor using its two connected nodes. Modified nodal analysis solves balanced and unbalanced bridge networks.
Why does a singular matrix error appear?
The circuit may contain floating nodes, impossible source combinations, or disconnected sections. Correct the node connections and calculate again.
How is Thevenin resistance calculated?
Independent voltage sources are shorted and current sources are opened. A one-ampere test source is then applied across the terminals.
What does negative source power mean?
Negative absorbed power means that the source delivers energy. Positive absorbed power means that the source receives energy from the circuit.
How does tolerance simulation work?
Each resistor is randomly varied within its tolerance model. Repeated solves estimate mean, spread, limits, and a ninety-five percent interval.
Is the thermal result exact?
No. It uses entered thermal resistance and calculated dissipation. Real temperatures also depend on airflow, mounting, enclosure, and nearby components.
Can I enter kilo-ohms directly?
Yes. Enter the numeric value and select kΩ. The calculator converts all resistance values into base ohms before solving.
Can results replace laboratory testing?
No. The calculator supports design analysis and checking. Verify important circuits using datasheets, measurement equipment, and appropriate engineering review.