What are the conversion relationships between charge units?
The SI base unit for electric charge is the coulomb (C), and prefixed units use a factor of 1000 between each: 1 C = 1,000 mC (millicoulombs) = 1,000,000 μC (microcoulombs) = 1,000,000,000 nC (nanocoulombs). Adjacent units differ by a factor of 10³: 1 mC = 1000 μC, 1 μC = 1000 nC. That is, moving right from C → mC → μC → nC multiplies by 1000, moving left divides by 1000 - standard SI thousand-fold scaling.
What is the relationship between electric charge (coulombs) and battery capacity (ampere-hours Ah)?
Both measure electric charge, just in different units. Based on the definition of current Q = I × t (charge = current × time): 1 C = 1 A·s (charge carried by 1 ampere flowing for 1 second), so 1 Ah = 1 A × 3600 s = 3600 C. A fully charged 3000 mAh phone battery stores about 3×3600 = 10,800 C of charge. This tool focuses on SI charge unit (C/mC/μC/nC) conversion; for Ah↔C conversion, manually multiply or divide by 3600.
What is the elementary charge e? How does it relate to coulombs?
The elementary charge e ≈ 1.602176634 × 10⁻¹⁹ C (exact value per 2019 SI redefinition), is the electric charge carried by one electron (-e) or one proton (+e), the smallest quantized free charge unit. One coulomb equals approximately 6.2415 × 10¹⁸ electrons' total charge. This tool focuses on SI engineering units; elementary charge is provided as a physical constant reference. For e ↔ nC conversion, manually multiply/divide by 1.602×10⁻¹⁰ nC/e.
How do you calculate charge in capacitor energy storage formulas? Is it related to capacitance conversion?
Charge stored in a capacitor is Q = C × U (capacitance × voltage), where Q is in coulombs (C), C in farads (F), U in volts (V). For example, charging a 100μF capacitor to 10V stores charge Q = 100×10⁻⁶ F × 10 V = 10⁻³ C = 1 mC = 1000 μC. This tool helps you quickly convert Q results between C/mC/μC/nC, convenient to use alongside the capacitance converter.
What order of magnitude is typical for electrostatic discharge (ESD) charge?
Common static electricity magnitudes in daily life: a human body walking in a dry environment can carry 0.1~1 μC (100~1000 nC) of charge; while discharge voltages can reach thousands to tens of thousands of volts, total energy is low (millijoule level) and usually not harmful to humans, but sufficient to damage CMOS chips (ESD-sensitive device damage thresholds can be as low as 100 nC or 100V HBM); sparks from removing a sweater are about a few μC; a single lightning strike is about 10~20 C, a very large amount of charge. Circuit design ESD protection TVS diodes, varistors and other component selection involves these magnitudes.
What is the relationship between Faraday's constant and coulombs? How is it used in electrolysis calculations?
Faraday's constant F = 96,485.3321 C/mol (exact value per 2019 SI definition), represents the total charge carried by 1 mole of electrons (Avogadro's number NA of electrons), F = NA × e ≈ 6.022×10²³ × 1.602×10⁻¹⁹ ≈ 96485 C/mol. Electrolysis law: mass of substance deposited m = (Q × M) / (z × F), where Q is charge passed (C), M is molar mass, z is charge number. Electroplating, water electrolysis, battery charge/discharge calculations all use this constant; this tool can first unify Q calculated from current×time to C before substitution.
How do you convert between current (amperes) and charge (coulombs)?
Current is defined as the charge passing through a conductor cross-section per unit time: I = Q / t, so Q = I × t. 1 ampere means 1 coulomb of charge flows per second (1 A = 1 C/s). For example, charging a battery: 2A charging for 1 hour (3600 seconds), passed charge Q = 2 × 3600 = 7200 C = 7.2 kC. This tool can further convert calculated C to mC/μC/nC for readability.
Why do people often write uC instead of μC?
μ is the Greek letter Mu, not available on standard English keyboards; early electronic circuit simulation software (SPICE), C programming, ASCII serial debugging, screen printing and other scenarios made μ inconvenient to input, so the electronics engineering industry widely used the Latin letter u instead of μ (u sounds similar to μ), uC = μC is a conventional notation (e.g., 10uC = 10μC). Some older literature uses mc, microcoulomb, etc.; current standards recommend μC or uC.
Why are charge unit conversions all factors of 1000 instead of 1024?
Electric charge is an SI unit physical quantity; all prefixes (m, μ, n, p) are strictly defined by powers of 10 (10⁻³, 10⁻⁶, 10⁻⁹, 10⁻¹²), with a conversion factor of 1000. Only computer storage (bytes B) uses binary conversion of 1024 (1KB=1024B); all physical units strictly use 1000. Therefore charge, voltage, current, capacitance, resistance, frequency, power and other electrical unit conversions all use 1000 factors. This tool calculates strictly per SI prefix definitions with no error.
Why isn't picocoulomb (pC) included? What if I need to convert pC?
This tool currently covers the four most commonly used SI charge units: C/mC/μC/nC. If you need pC (picocoulombs, 10⁻¹² C), you can manually convert using thousand-fold relationships: 1 nC = 1000 pC, 1 pC = 0.001 nC, i.e., nC value × 1000 = pC value. In physics, elementary charge e ≈ 1.602×10⁻¹⁹ C = 1.602×10⁻⁷ nC = 1.602×10⁻⁴ pC, in the sub-pC range (particle physics, nuclear radiation detector fields).
How accurate are conversion results? How do I read scientific notation?
Conversions use JavaScript double-precision floating-point numbers (IEEE 754, ~15-17 significant digits), factors per exact SI definitions (1mC=10⁻³C, 1μC=10⁻⁶C, 1nC=10⁻⁹C), relative error on the order of 10⁻¹², far exceeding engineering and physics experiment precision requirements. When result absolute value is less than 0.0001 or greater than 10000, superscript scientific notation is automatically used (e.g., 1.60×10⁻¹⁹ represents 0.0000000000000000001602); internally the full value is preserved, this is only display optimization.
Will my entered charge values be uploaded? Is my data private and secure?
Completely no upload. The entire conversion logic runs in pure frontend JavaScript in your local browser, entered values make no network requests, servers cannot see any of your data. Input content is cleared immediately when you close the tab, no cookies or localStorage are used for storage. Suitable for student exam review, laboratory data processing, enterprise R&D and other data privacy-sensitive scenarios.
