See current, drops, and wattage for every part. Tune assumptions with temperature and wiring resistance. Make better design choices and reduce hidden losses today.
| Supply (V) | Resistors (Ω) | Wire (Ω) | Current (A) | Drops (V) |
|---|---|---|---|---|
| 12 | 100, 220, 330 | 0.05 | ≈ 0.0185 | ≈ 1.85, 4.07, 6.11 (wire ≈ 0.00) |
| 24 | 470, 1000 | 0.20 | ≈ 0.0163 | ≈ 7.66, 16.30 (wire ≈ 0.00) |
| 5 | 10, 47, 68 | 0.10 | ≈ 0.0394 | ≈ 0.39, 1.85, 2.68 (wire ≈ 0.00) |
Voltage drop is the portion of supply voltage consumed by each series element. In practical builds, unexpected drop can dim LEDs, reduce motor torque, or create brownout resets. Knowing the drop distribution helps you confirm design intent and diagnose faults.
In a true series path, the same current flows through every resistor and connection. Once total resistance is known, current follows directly from Ohm’s law. Each component’s voltage drop is proportional to its resistance, making ratios as important as absolute values.
Leads, connectors, and PCB traces often add small resistance that becomes significant at higher current. Even 0.10 Ω at 5 A produces 0.5 V drop and 2.5 W heat. Modeling a single “wire resistance” captures this effect and prevents optimistic calculations.
Power loss in each element is P = I²R. A modest resistance can become a heater when current rises. Comparing component power helps you select appropriate wattage ratings, avoid discoloration, and manage enclosure temperatures.
Many conductors increase resistance with temperature. A linear coefficient model estimates how resistance shifts from a reference point. When you apply α, the calculator adjusts both resistor and wiring values, letting you evaluate warm operation versus room temperature.
Component tolerance means the actual resistance may differ from the nominal value. While this tool uses nominal values for clarity, listing tolerance next to each part supports quick worst-case thinking. For critical designs, test with min and max resistance scenarios.
Measure voltage at nodes along the series chain and compare the observed drops to the predicted pattern. A larger-than-expected drop often points to a damaged resistor, weak solder joint, or corroded connector. A smaller drop can indicate a bypass or short.
When drops are known, you can re-balance resistances to set target voltages, reduce wasted power, or move heat away from sensitive parts. Documenting results in CSV or PDF supports repeatable builds and clear maintenance records.
No. Parallel circuits split current among branches. This calculator assumes one current through all parts. Use a parallel network tool when branches share the same voltage.
Wires, traces, and connectors add resistance that increases drop and heat. Adding a single lumped wiring value often matches real builds better than ideal resistor-only calculations.
The calculator uses I = V / Rtotal, where Rtotal is the sum of all resistors plus wiring resistance. That same current is used to compute each voltage drop.
It is the percentage of the supply voltage dropped by a component. It helps you see which resistor dominates the total drop and which changes will matter most.
The α model is a practical approximation for many conductors. For precision components or wide ranges, consult the part datasheet or use measured resistance at operating temperature.
Worst-case analysis depends on whether values shift high or low together. The tool lists tolerances so you can test scenarios by editing values to minimum and maximum combinations.
The PDF export prioritizes portability and speed. It includes the key computed values and a readable breakdown. For rich reports, export CSV and format it in your preferred tool.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.