Find equivalent resistance, circuit current, voltage drops, power, and resistor loading for any ideal series circuit.
| Resistor | Resistance | Voltage Drop | Current | Power | Voltage % | Rating | Status |
|---|---|---|---|---|---|---|---|
| No calculation yet. | |||||||
Total series resistance: Rₜ = R₁ + R₂ + ... + Rₙ
Circuit current: I = V / Rₜ
Voltage drop: Vₙ = I × Rₙ
Power: Pₙ = I²Rₙ and Pₜ = VI
For an ideal series circuit, the same current flows through every resistor. Individual voltage drops should add to the source voltage.
A series circuit connects components along one continuous electrical path. The same current therefore passes through every resistor. This makes series circuits straightforward to analyze with Ohm’s law. First, add all resistor values to obtain the total resistance. A larger total resistance reduces current when the supply voltage stays unchanged.
The calculator converts every entered resistance into ohms internally. It also converts the source voltage into volts. It then divides voltage by total resistance to find current. Each resistor receives a voltage drop proportional to its resistance. Larger resistors therefore receive a larger share of the source voltage.
Power is also important when selecting real resistors. Each resistor converts electrical energy into heat. Its power dissipation equals current squared multiplied by resistance. If you enter a resistor power rating, the calculator compares calculated dissipation with that rating. A warning appears when calculated power meets or exceeds the entered limit.
Kirchhoff’s voltage law provides a useful accuracy check. In a closed series loop, all resistor voltage drops should equal the applied source voltage. Small differences may appear only because displayed values are rounded. The calculator reports the summed voltage drops and their difference from the source.
Use this tool for classroom exercises, circuit planning, resistor networks, voltage-divider checks, and basic electronics experiments. Always confirm component tolerances, temperature effects, maximum voltage, and power ratings before building hardware. Real circuits can differ from ideal calculations because wires, sources, meters, and components add resistance. Proper safety practices remain essential when working with high voltage or high power. The calculator is best used as an engineering aid, not a replacement for safe circuit design.
For quick comparisons, change one resistor and recalculate the circuit. This reveals how resistance changes current, voltage division, and heating. Such comparisons are useful when choosing standard resistor values or checking alternate circuit designs before testing hardware.
| Supply | Series Resistors | Total Resistance | Current |
|---|---|---|---|
| 5 V | 100 Ω + 150 Ω + 250 Ω | 500 Ω | 10 mA |
| 12 V | 100 Ω + 200 Ω + 300 Ω | 600 Ω | 20 mA |
| 24 V | 1 kΩ + 2.2 kΩ + 3.3 kΩ | 6.5 kΩ | 3.692 mA |
| 9 V | 470 Ω + 1 kΩ | 1.47 kΩ | 6.122 mA |
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.