🎓 Physics • Electricity
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Resistance Calculator
Computes resistance in Ohms from voltage and current, plus series and parallel combination networks.
Ohm’s Law & Electrical Power Calculator
Enter any 2 known values — the remaining 2 are solved instantly via V = IR and P = VI.
Standard Circuit Presets:
Unit: V
Unit: A
Unit: Ohms (Ω)
Unit: W (J/s)
Dynamic DC Circuit SchematicConventional Current Flow (Clockwise)
Voltage (V)
12 V
Current (I)
2 A
Resistance (R)
6 Ω
Power (P)
24 W
Step-by-Step Derivation
Given: Voltage V = 12 V, Current I = 2 A
1. Resistance: R = V / I = 12 / 2 = 6.0000 Ω
2. Power: P = V × I = 12 × 2 = 24.0000 W
What is Electrical Resistance?
Resistance measures opposition to the flow of electrical current, converting electrical energy into heat.
Formula & Step-by-Step Calculation
R = V / I, R_series = R₁ + R₂, 1/R_parallel = 1/R₁ + 1/R₂
Ohm’s law and resistor combination laws.
Worked Step-by-Step Examples
Example 1
Two 100 Ω resistors in parallel
Solution: 50 Ω
• (100 × 100) / (100 + 100) = 50 Ω
Common Real-World & Academic Use Cases
- ✓ Resistor network equivalent values
- ✓ Heating element resistance
- ✓ Trace resistance on PCBs
How to Use the Resistance Calculator
1
Choose Mode
Select Ohm's law or Series/Parallel.
2
Enter Resistances
Input values in Ohms.
3
View Equivalent
Inspect total resistance.
Frequently Asked Questions
Q: Why does parallel resistance decrease?
Connecting resistors in parallel provides multiple parallel paths for current to flow.