Calculator Inputs
This page uses a single stacked page layout, while the calculator inputs switch to 3 columns on large screens, 2 on medium screens, and 1 on mobile.
Example Data Table
| Case | Network Type | Input Values | Equivalent Resistance | Notes |
|---|---|---|---|---|
| 1 | Series | 10 Ω, 20 Ω, 30 Ω | 60.0000 Ω | All resistors add directly. |
| 2 | Parallel | 10 Ω, 20 Ω, 30 Ω | 5.4545 Ω | Sum conductances, then invert. |
| 3 | Mixed | 10+5 Ω, 20+30 Ω, 15 Ω | 6.5217 Ω | Each branch is series, then branches are parallel. |
Formula Used
Series network: Req = R1 + R2 + R3 + ... + Rn
Parallel network: 1 / Req = (1 / R1) + (1 / R2) + (1 / R3) + ... + (1 / Rn)
Mixed network: First calculate each branch sum in series, then calculate the parallel equivalent of those branch totals.
Temperature adjustment: RT = Rref × [1 + α × (T - Tref)], where α = ppm / 1,000,000.
Tolerance range: The calculator applies the tolerance percentage to the temperature-adjusted component values, then recalculates the network for minimum and maximum equivalent resistance.
Electrical outputs: When source voltage is provided, the calculator also uses I = V / R and P = V × I to estimate current and power.
How to Use This Calculator
Choose the network type first. Use series for one current path, parallel for multiple direct branches, and mixed when each branch contains resistors in series.
Select the input unit. The calculator accepts ohms, kilo-ohms, and mega-ohms, then converts everything internally to ohms for consistent calculations.
Enter resistor values for series or parallel networks in one box. Separate values with commas, spaces, or line breaks.
For mixed networks, enter one branch per line or use semicolons between branches. Inside each branch, separate resistors with commas.
Add optional settings such as source voltage, tolerance, temperature coefficient, operating temperature, reference temperature, and any extra series resistance from leads or contacts.
Press the calculate button. The result appears below the header and above the form, followed by a detailed breakdown and export buttons.
Use the CSV and PDF buttons to save the calculated summary and branch or component details for documentation or later review.
FAQs
1. What network types does this calculator support?
It supports pure series networks, pure parallel networks, and mixed networks where each branch contains series resistors and all branches are connected in parallel.
2. How do I enter a mixed resistor network?
Enter one branch per line or separate branches with semicolons. Inside each branch, separate the series resistors with commas, such as 10,5; 20,30; 15.
3. Why does the calculator ask for temperature coefficient?
Resistance changes with temperature. The coefficient lets the calculator adjust each entered resistor from the reference temperature to the operating temperature for a more realistic result.
4. What does the tolerance range represent?
It shows the estimated minimum and maximum equivalent resistance after applying the selected tolerance percentage to the temperature-adjusted component values.
5. Can I enter values in kΩ or MΩ?
Yes. Choose the appropriate unit before calculating. The tool converts the entries internally, then reports final resistance values in ohms for exact comparison.
6. What happens if I leave source voltage blank?
The calculator still returns equivalent resistance, conductance, and tolerance range. Current, voltage drop, and power outputs require a source voltage value.
7. Why is extra series resistance useful?
It helps model wiring, contacts, lead resistance, connectors, or test fixture losses that add directly in series with the main resistor network.
8. Can this replace a full circuit simulator?
No. It is ideal for equivalent resistance and simple DC estimates, but it does not model reactive parts, nonlinear devices, frequency response, or transient effects.