CGS e.s. unit to Milliampere
CGS ESU
mA
Conversion History
| Conversion | Reuse | Delete |
|---|---|---|
1 CGS ESU (CGS e.s. unit) → 3.335641e-7 mA (Milliampere) Just now |
Quick Reference Table (CGS e.s. unit to Milliampere)
| CGS e.s. unit (CGS ESU) | Milliampere (mA) |
|---|---|
| 1 | 0.0000003335641 |
| 10 | 0.000003335641 |
| 100 | 0.00003335641 |
| 1,000,000 | 0.3335641 |
| 1,000,000,000 | 333.5641 |
| 3,000,000,000 | 1,000.6923 |
About CGS e.s. unit (CGS ESU)
The CGS electrostatic unit (CGS e.s. unit) of current equals approximately 3.335641×10⁻¹⁰ amperes, identical to the statampere or ESU of current. In the CGS electrostatic subsystem, current is defined as statcoulombs per second, giving one CGS e.s. unit per second of charge flow. The CGS-ESU system places Coulomb s law in a clean constant-free form but produces cumbersome dimensions for magnetic quantities. It was used in early electrostatics, cathode-ray tube physics, and vacuum science. All modern work uses SI. The factor 1/c (in CGS cm/s) converts ESU current to SI amperes.
1 CGS e.s. unit ≈ 3.336×10⁻¹⁰ A. A 1 A current equals about 3×10⁹ CGS e.s. units — illustrating the enormous scale difference between the ESU and SI systems.
About Milliampere (mA)
The milliampere (mA) equals one thousandth of an ampere (10⁻³ A) and is the practical unit for most consumer electronics and lighting circuits. USB 2.0 ports supply up to 500 mA; USB-C Power Delivery can reach 5,000 mA (5 A). A standard 5 mm indicator LED operates at 10–20 mA; mid-power LED drivers supply 100–350 mA. Human perception of electric shock begins near 1 mA; currents above 10 mA cause involuntary muscle contraction, and above 100 mA can be lethal. Wireless sensors, earphones, and small motors typically draw single-digit to low-hundreds of milliamperes.
A USB 2.0 port provides up to 500 mA for charging. A standard 5 mm indicator LED operates at around 20 mA.
CGS e.s. unit – Frequently Asked Questions
Why is the CGS e.s. unit so different in magnitude from the CGS e.m. unit?
The e.m. unit equals 10 A while the e.s. unit equals 3.3 × 10⁻¹⁰ A — a ratio of about 3 × 10¹⁰, which is the speed of light in cm/s. This enormous factor reflects the fundamental relationship c² = 1/(ε₀μ₀). The two systems were designed to simplify different sets of equations, and the speed of light is the price of bridging them.
What made the CGS electrostatic system useful for early vacuum physics?
In vacuum tubes and cathode ray experiments, electrostatic forces dominate — no magnetic materials, no currents in bulk conductors. The ESU system made Coulomb's law beautifully simple: F = q₁q₂/r² with no constants. For computing electron trajectories in early TV tubes and oscilloscopes, this simplicity was genuinely helpful.
How did early CRT televisions use electrostatic units in beam deflection design?
Early cathode ray tubes used electrostatic deflection plates to steer the electron beam. Engineers working in CGS-ESU could calculate beam deflection angles directly from plate voltage and geometry using Coulomb's law without extra constants. The tiny ESU currents matched the actual beam currents (microamperes), making the numbers more intuitive than working in amperes for these minuscule electron flows.
How do I know if an old paper is using CGS e.s. or CGS e.m. units?
Check the context and the magnitude of numbers. If currents are tiny numbers where you would expect amperes, it is ESU. If they are 1/10 of expected ampere values, it is EMU. Good papers state which system they use, but many older ones do not. The equations themselves also differ — look for factors of c or 4π.
Could the CGS electrostatic system handle magnetic phenomena?
Technically yes, but clumsily. In pure CGS-ESU, the magnetic field has dimensions involving the speed of light, and equations for inductance and magnetic force become awkward. This is exactly why the Gaussian hybrid was invented — it uses ESU for electric quantities and EMU for magnetic ones, giving clean equations for both.
Milliampere – Frequently Asked Questions
How many milliamps is dangerous to a human?
The danger thresholds for 50/60 Hz AC are roughly: 1 mA (tingling), 10–20 mA (muscle lock — you cannot let go), 75–100 mA (ventricular fibrillation), and 200+ mA (cardiac arrest and burns). DC is somewhat less dangerous at the same current. Duration matters enormously — 100 mA for 1 second is more lethal than 100 mA for 10 ms.
Why is my phone charger rated in milliamps when it charges at 2 amps?
Battery capacity is rated in milliampere-hours (mAh), not milliamps. A 4,000 mAh battery holds 4,000 mA for one hour (or 2,000 mA for two hours). The charger delivers 2 A (2,000 mA) of current, and it takes about 2 hours to fill that 4,000 mAh battery from empty.
What is the milliamp draw of common household items?
A wireless earbud draws 5–15 mA during playback. A TV remote uses about 10 mA when pressing a button. An LED nightlight consumes 20–50 mA. A smoke detector in standby draws 10–30 μA (0.01–0.03 mA) — so low it runs on a 9V battery for years.
Why do LED specifications always mention 20 mA?
Standard 5 mm indicator LEDs were designed around a 20 mA operating point — bright enough to see clearly, low enough to avoid overheating the tiny die. All datasheet specs (luminous intensity, color, forward voltage) are measured at this "test current." High-power LEDs use 350 mA or 700 mA as their reference instead.
How does milliamp-hour (mAh) relate to milliamp (mA)?
Milliamp-hours measure charge capacity; milliamps measure current flow rate. A 2,000 mAh battery can deliver 2,000 mA for 1 hour, or 200 mA for 10 hours, or 20 mA for 100 hours — current times time equals capacity. Dividing mAh by mA gives approximate runtime in hours.