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⚡ Parallel Resistor Calculator

Calculate equivalent resistance, current distribution, and power analysis for parallel resistor networks with detailed step-by-step solutions.

Calculation Type

Input Parameters

┌─── R1 ───┐
────┤ ├────
└─── R2 ───┘
Parallel Resistor Network
Parallel Resistance Formula
1/Req = 1/R1 + 1/R2
Equivalent resistance is always less than the smallest resistor

Results & Analysis

Enter resistor values and click Calculate to see parallel circuit analysis

Parallel Resistor Theory

Equivalent Resistance

In parallel circuits, the equivalent resistance is always less than the smallest individual resistor.

  • 1/Req = 1/R1 + 1/R2 + 1/R3 + ...
  • For two resistors: Req = (R1×R2)/(R1+R2)
  • Adding more resistors decreases Req
  • Provides multiple current paths

Current Distribution

Current divides inversely proportional to resistance values.

  • Voltage across all resistors is equal
  • Current: I = V/R for each branch
  • Smaller resistors carry more current
  • Total current = sum of branch currents

Applications

  • Current Dividers: Split current between paths
  • Redundancy: Backup paths if one fails
  • Power Distribution: Multiple loads
  • Precision Resistors: Custom resistance values

HOW TO USE

Enter two or more resistance values separated in the input fields. Click Calculate to find the equivalent parallel resistance, current through each branch, and power distribution.

FORMULA USED

1/R_total = 1/R1 + 1/R2 + 1/R3 + ...
For two resistors: R_total = (R1 × R2) ÷ (R1 + R2)
Current: I_n = V ÷ R_n

WORKED EXAMPLE

R1=100Ω and R2=100Ω in parallel: R_total = (100×100)÷(100+100) = 50 Ω. Parallel resistance is always less than the smallest resistor.

FREQUENTLY ASKED QUESTIONS

Q: Why is parallel resistance less than any individual resistor?

A: Adding parallel paths gives current more routes to flow, reducing overall opposition. Each added resistor lowers total resistance.

Q: What happens to voltage in parallel resistors?

A: Voltage is the same across all parallel resistors. Current divides inversely proportional to resistance.

Q: How do I add many resistors in parallel?

A: Use: R_total = 1 ÷ (1/R1 + 1/R2 + 1/R3 + ...). This calculator handles multiple resistors automatically.

Q: When are parallel resistors used?

A: To reduce total resistance, increase current capacity, provide redundancy, or create current dividers in circuits.