Hukum Ohm Rumus (V = IR): Gratis Calculator & Usahaed Examples

Use V = IR (the IR formula) for voltage, current, or resistance. mA/kΩ traps, worked examples, and a free Ohm's law calculator.

Cara menggunakan Hukum Ohm (Quick Answer)

Ohm's law is V = I R (often written V = IR or v = ir). Tegangan equals current times resistance. If you know any two of V, I, and R, solve for the third.

  • V = I × R — find voltage.
  • I = V / R — find current (the “IR formula” rearranged).
  • R = V / I — find resistance.
  • Konversi mA → A (÷ 1000) and kΩ → Ω (× 1000) before substituting.

    • Need a checked number now? Open the free Ohm's law calculator (V = IR) — then come back for unit traps and worked examples.

    What Is V = IR (the IR Rumus)?

    V is voltage in volts, I is current in amperes, and R is resistance in ohms. For an ohmic resistor they stay in proportion: raise V at fixed R and I rises; raise R at fixed V and I falls.

    Students often search “ir formula” or “v = ir” meaning the same relationship. Once two values are known, the third is fixed — that is why a rearranging calculator covers most homework checks.

    Rearrangements

  • V = I × R.
  • I = V / R.
  • R = V / I.

    • Solve any form on the free Ohm's law calculator.

    When Hukum Ohm Applies

    Use it when the problem treats the component as an ohmic resistor — a single R that does not change with voltage in the range you care about. Metal-film resistors in lab kits are the usual case.

    Do not force a single R onto diodes, LEDs, or other non-linear devices unless the question says to.

    Unit Traps

    Milliamps vs amperes

    Konversi before dividing: 30 mA = 0.030 A. Using 9 / 30 instead of 9 / 0.030 makes R wrong by 1000×.

    Kilo-ohms vs ohms

    2.2 kΩ = 2200 Ω. Leaving kΩ as 2.2 in V = IR breaks the answer.

    Daya vs Ohm's law

    Watts use P = V I (or I²R, V²/R). When the unknown is power, use the electric power calculator — not Ohm's law alone.

    Usahaed Examples

    Example 1: I from 12 V and 4 Ω

    I = V / R = 12 / 4.0 = 3.0 A.

    Example 2: R from 9 V and 30 mA

    30 mA = 0.030 A. R = 9 / 0.030 = 300 Ω.

    Example 3: V from 0.025 A and 1.2 kΩ

    R = 1200 Ω. V = I R = (0.025)(1200) = 30 V.

    Check Examples 1–3 on the Ohm's law calculator.

    Hukum Ohm vs Dividers and Networks

    Ohm's law handles one resistance relationship. For two resistors sharing a supply, use a voltage divider. For series/parallel pairs, find equivalent R first, then apply V = IR.

    Tegangan divider calculator.

    Series–parallel resistance calculator.

    Electric power (P = VI).

    Kesalahan umum

  • Leaving current in mA while R is in ohms.
  • Treating kΩ as ohms in V = IR.
  • Writing I = R/V instead of I = V/R.
  • Applying a fixed R to a clearly non-ohmic device.

    • Gratis Hukum Ohm Calculator

    Use the free Ohm's law calculator to solve V = IR for voltage, current, or resistance with step-by-step working.

    Electric power calculator.

    Tegangan divider calculator.

    Master V = IR with clean amperes and ohms — then verify every homework answer.

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