Voltage Calculator for Series Circuit
Enter values below. The calculator accepts comma, space, semicolon, or new-line separated resistor values.
Formula Used
How to Use This Calculator
- Enter the supply voltage and select the matching voltage unit.
- Type all series resistor values in the text box.
- Select the unit used by your resistor list.
- Add source resistance if wiring, battery, or supply resistance matters.
- Add resistor tolerance and supply tolerance for a practical range.
- Add temperature coefficient and temperature change when heat matters.
- Press the calculate button to show results above the form.
- Use the CSV or PDF button to export the report.
Example Data Table
| Example | Supply Voltage | Resistors | Total Resistance | Current | Purpose |
|---|---|---|---|---|---|
| LED string check | 12 V | 100, 150, 220 Ω | 470 Ω | 25.53 mA | Basic current planning |
| Sensor divider chain | 5 V | 1000, 2200, 3300 Ω | 6500 Ω | 0.769 mA | Signal scaling |
| Battery test load | 24 V | 47, 68, 100 Ω | 215 Ω | 111.63 mA | Load estimation |
Series Circuit Voltage Guide
Why series voltage matters
A series circuit gives one clear current path. The same current flows through every resistor. Voltage is shared by the parts. The share depends on each resistance value. A larger resistor receives a larger voltage drop. This idea is called voltage division. It is common in sensors, bias networks, lights, and test benches.
Using the calculator in practice
This calculator helps you study the full chain. Enter the source voltage first. Then add resistor values in order. You may use commas, spaces, or new lines. Select the common unit for the list. Add source resistance when the supply or wiring is not ideal. Add tolerance to see a practical current range. Add temperature data when hot parts change resistance.
Reading the results
The main answer shows equivalent resistance, loop current, total drop, and power. The table shows each resistor. It lists adjusted resistance, voltage drop, share of supply, and heat in watts. These values help you choose parts. The largest power value needs the most attention. Compare it with the watt rating. Leave margin for warm cases and long service life.
Good checking habits
Check the unit before you press calculate. A kilohm value is one thousand ohms. A millivolt source is much smaller than one volt. Review the graph for unusual drops. A tall bar usually marks the largest resistor. The current range shows how tolerances can shift every answer. Use the export buttons to save your work. Keep the file with your lab notes or design record. Repeat the check after any component change. Small edits can move current, power, and voltage balance in every resistor. Document assumptions clearly when you share the exported report later.
Design notes
Series design is simple, but limits still matter. All parts carry the same current. One open part stops the whole circuit. Real supplies have resistance. Leads and contacts also create small drops. These details can matter in low voltage circuits. They also matter in precision dividers. Use tolerance results before final design. Use a meter when safety or calibration is important. This tool supports learning, planning, and fast checks. It does not replace local electrical rules.
FAQs
1. What is a series circuit?
A series circuit has one path for current. Every resistor carries the same current. The supply voltage is divided across the resistors based on their resistance values.
2. How is voltage divided in a series circuit?
Voltage divides in proportion to resistance. A higher resistance gets a larger voltage drop. The sum of all resistor voltage drops equals the applied voltage, minus internal source losses.
3. Is current the same through every resistor?
Yes. In a series circuit, the same current flows through each component. That is why one current value is used for every voltage and power calculation.
4. Why add source internal resistance?
Real batteries, supplies, wires, and contacts have resistance. This resistance causes an extra voltage drop. Adding it gives a more realistic current and load voltage result.
5. What does resistor tolerance mean?
Resistor tolerance shows possible variation from the labeled value. A 5% resistor can be slightly higher or lower. This calculator estimates current range using that variation.
6. Why include temperature coefficient?
Some resistors change value when temperature changes. The coefficient tells how many parts per million change per degree Celsius. This helps estimate hot or cold behavior.
7. How do I choose resistor watt rating?
Compare calculated resistor power with the part rating. Use a rating higher than the expected power. Extra margin improves reliability and reduces heat stress.
8. Can this calculator be used for AC circuits?
It is mainly for resistive series circuits. For AC circuits with capacitors or inductors, impedance and phase angle are needed for accurate voltage calculations.