Welcome to Resistor Calculator Pro
This tool provides easy-to-use calculators for common resistor configurations. Whether you're dealing with simple series or parallel networks, transforming delta to star (or star to delta), or combining series and parallel groups, we have you covered. Built with a responsive design to work on PCs, tablets, and phones.
- Ohm's Law (V = IR): Voltage (V) across a resistor is the product of the current (I) flowing through it and its resistance (R).
- Kirchhoff's Current Law (KCL): The sum of currents flowing into a node equals the sum of currents flowing out of that node.
- Kirchhoff's Voltage Law (KVL): The sum of voltage drops around any closed loop in a circuit is zero.
- Joule's Law (P = I²R): The power (P) dissipated by a resistor is proportional to the square of the current (I) times the resistance (R).
Understanding these laws is crucial for analyzing and designing electronic circuits.
- Series: Resistors in series add up to give the total resistance.
- Parallel: The reciprocal of the total resistance is the sum of the reciprocals of each resistor.
- Delta-Star & Star-Delta: Converts a triangle (Δ) resistor network into a star (Y) network, or vice versa.
- Series-Parallel: Combines groups of series resistors that are then connected in parallel (or vice versa).
Select configuration type and enter resistor values:
Calculate the resistance of a conductor using R = ρ × (L / A), where:
- ρ: Resistivity (Ω·m)
- L: Length of the conductor (m)
- A: Cross-sectional area (m²)
Identify resistor values by selecting the color bands below. (4-Band Example)
Resistor Color Code Reference
| Color | 1st & 2nd Band Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | ×1 | - |
| Brown | 1 | ×10 | ±1% |
| Red | 2 | ×100 | ±2% |
| Orange | 3 | ×1k | - |
| Yellow | 4 | ×10k | - |
| Green | 5 | ×100k | ±0.5% |
| Blue | 6 | ×1M | ±0.25% |
| Violet | 7 | ×10M | ±0.1% |
| Gray | 8 | ×100M | ±0.05% |
| White | 9 | ×1G | - |
| Gold | - | ×0.1 | ±5% |
| Silver | - | ×0.01 | ±10% |
A resistor is a passive electronic component that implements electrical resistance as a circuit element. They reduce current flow, adjust signal levels, divide voltages, and more.
- Series: Resistors in series add directly.
- Parallel: The reciprocal of total resistance is the sum of reciprocals of each resistor.
- Delta-Star & Star-Delta: Convert between Δ (triangle) and Y (star) configurations.
- Series-Parallel: Groups of series resistors connected in parallel or vice versa.
Use the calculator above to compute your resistor values quickly and accurately. Refer to the color code table to identify resistor markings with ease.