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Current Unit Converter

Convert electric current between amperes, milliamperes, microamperes, nanoamperes, and picoamperes.

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Formula

1 A = 10³ mA = 10⁶ μA = 10⁹ nA = 10¹² pA

How It Works

Electric current is measured in amperes (A), the SI base unit defined as the flow of one coulomb of charge per second. In electronics, sub-units are essential: milliamperes (mA, 10⁻³ A) for typical ICs and LEDs, microamperes (μA, 10⁻⁶ A) for low-power sensors and sleep-mode circuits, nanoamperes (nA, 10⁻⁹ A) for op-amp bias currents and CMOS leakage, and picoamperes (pA, 10⁻¹² A) for photodetector dark currents.

Worked Example

An MCU in sleep mode draws 10 μA: 10 μA = 0.01 mA = 10,000 nA = 10,000,000 pA = 0.00001 A. A motor driver outputs 2 A: 2 A = 2000 mA = 2,000,000 μA = 2 × 10⁹ nA.

Practical Tips

  • ✓Battery-powered designs should target μA-range sleep currents; even 1 mA of quiescent draw will drain a 1000 mAh battery in ~42 days.
  • ✓LED current is typically 10–20 mA for standard indicators; reduce to 1–5 mA for low-power designs using high-efficiency LEDs.
  • ✓Op-amp input bias currents range from pA (JFET input) to μA (BJT input); choose the right type to minimize offset voltage errors in high-impedance circuits.

Common Mistakes

  • ✗Confusing mA (milliampere) with μA (microampere) — they differ by 1000×; a device drawing 10 μA draws 1000× less than one drawing 10 mA.
  • ✗Forgetting to account for inrush current, which can be 5–10× the steady-state current and may trip protection circuits.
  • ✗Measuring nA-range currents with a standard DMM — the input burden voltage can corrupt the reading; use a picoammeter or transimpedance amplifier instead.

Frequently Asked Questions

Most MCU GPIO pins source/sink 8–20 mA per pin, with a total package limit of 100–200 mA. Always check both per-pin and total current ratings.
Use a DMM on its μA range, or better, use a shunt resistor with amplifier. For pA-range measurement, a transimpedance amplifier (TIA) circuit converts current to a measurable voltage.
Quiescent current (Iq) is the current an IC draws with no load connected, representing its own internal operating overhead. Low Iq is critical for battery life in IoT and wearable applications.
Photodiode dark current arises from thermally generated electron-hole pairs in the depletion region. It is extremely small (1–100 pA) but sets the detection noise floor in optical systems.

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