CalKit

Ohm's Law Calculator

Calculate voltage, current and resistance relationships.

A
Ω
전압 (V)
12.0000V

V = I × R = 2 × 6

상세 결과

전압 (V)12.0000 V
전류 (I)2 A
저항 (R)6 Ω
전력 (P = V × I)24.0000 W
사용 공식V = I × R

Overview

Calculate voltage, current, or resistance using Ohm's Law (V = IR). Essential for circuit design, component selection, and electrical safety analysis.

Formula

Voltage = Current × Resistance  (V = I × R)
Current = Voltage ÷ Resistance  (I = V / R)
Resistance = Voltage ÷ Current  (R = V / I)

Power: P = V × I = I²R = V²/R

Units: Voltage (V), Current (A), Resistance (Ω), Power (W)

How to Use

  1. 1Select the value you want to calculate (voltage, current, or resistance).
  2. 2Enter the other two known values.
  3. 3Check units carefully (mA, kΩ, etc.).
  4. 4Click calculate to see the result along with power dissipation.

Tips

  • ✔1 kΩ = 1,000 Ω, 1 MΩ = 1,000,000 Ω.
  • ✔1 mA = 0.001 A, 1 μA = 0.000001 A.
  • ✔LED resistor calculation: R = (Supply Voltage - LED Forward Voltage) ÷ Desired Current.
  • ✔Ohm's Law applies only to linear (ohmic) components. It cannot be directly applied to non-linear devices like diodes.

FAQ

Q. When does Ohm's Law not apply?

Ohm's Law does not directly apply to non-linear components such as diodes and transistors, components with significant temperature-dependent resistance, and superconductors.

Q. How do you calculate total resistance for series and parallel circuits?

Series: R_total = R1 + R2 + ... + Rn. Parallel: 1/R_total = 1/R1 + 1/R2 + ... + 1/Rn. The total resistance in a parallel circuit is always less than the smallest individual resistance.

Q. What level of current is dangerous for humans?

Human body resistance varies from 1,000 to 100,000 Ω depending on conditions. A current of about 30 mA or more can be life-threatening. Household voltage (110–240V) can easily produce dangerous current levels.

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