EMU of current to Nanoampere
EMU
nA
Conversion History
| Conversion | Reuse | Delete |
|---|---|---|
1 EMU (EMU of current) → 10000000000 nA (Nanoampere) Just now |
Quick Reference Table (EMU of current to Nanoampere)
| EMU of current (EMU) | Nanoampere (nA) |
|---|---|
| 0.1 | 1,000,000,000 |
| 0.5 | 5,000,000,000 |
| 1 | 10,000,000,000 |
| 5 | 50,000,000,000 |
| 10 | 100,000,000,000 |
| 30 | 300,000,000,000 |
| 100 | 1,000,000,000,000 |
About EMU of current (EMU)
The electromagnetic unit (EMU) of current equals exactly 10 amperes, numerically identical to the biot. It is the current unit native to the CGS electromagnetic (CGS-EMU) system, which dominated electrical physics from the mid-19th century until SI adoption in 1960. In CGS-EMU, the permeability of free space is defined as 1, giving the electromagnetic subsystem its characteristic form where magnetic force between parallel currents is expressed purely in dynes. The EMU of current appears in classical electrodynamics texts, historical measurement standards, and theoretical physics work using CGS-EMU conventions. All practical electrical measurement now uses SI amperes.
1 EMU of current = 10 A. A 50 A arc welding process carries 5 EMU. The unit is encountered primarily in pre-1960 scientific literature.
About Nanoampere (nA)
The nanoampere (nA) equals one billionth of an ampere (10⁻⁹ A) and is used for the smallest measurable electrical currents in precision instrumentation and low-power electronics. Electrochemical biosensors detecting glucose or DNA generate signals in the nanoampere range; implantable devices are designed to draw only a few nanoamperes in sleep states to extend battery life by years. Junction leakage currents in CMOS transistors and reverse-bias diode currents are also measured in nanoamperes. In electrochemistry, nanoampere-resolution galvanostat equipment is standard for corrosion studies and thin-film deposition research.
A glucose biosensor strip draws approximately 100–500 nA during a measurement. A low-power microcontroller in deep sleep typically consumes 1–100 nA.
EMU of current – Frequently Asked Questions
What does EMU stand for and why was it created?
EMU stands for "electromagnetic unit." In the 1860s–1870s, physicists needed separate unit systems for electrostatic and electromagnetic phenomena because they had not yet unified them. The EMU system was built around magnetic force between currents, while the ESU system was built around Coulomb's electrostatic force. The ratio between them turned out to be the speed of light — a clue that led to Maxwell's equations.
Is the EMU of current the same as a biot?
Yes, exactly. Both equal 10 amperes. The biot is the named unit; "EMU of current" is the generic label. It is like saying "SI unit of force" versus "newton" — same thing, different label. The CGS-EMU system also has named units for other quantities: the gauss (magnetic field), the oersted (magnetising field), and the maxwell (magnetic flux).
Why did physics abandon the EMU system?
The EMU system was awkward for practical electrical engineering — 1 EMU of resistance (the abohm) equals 10⁻⁹ ohms, making everyday values absurdly large numbers. The SI system, adopted in 1960, unified mechanical and electrical units into one coherent framework with human-scale values. Practicality won over tradition.
Where might I encounter EMU of current in old scientific papers?
Pre-1960 physics journals, particularly in geomagnetism, plasma physics, and early electrical standards work, routinely use EMU. Geophysicists measuring Earth's magnetic field historically reported results in CGS-EMU units (gauss, oersted, EMU). Some geophysics reference data still has not been converted to SI.
How did the speed of light connect the EMU and ESU systems?
Weber and Kohlrausch discovered in 1856 that the ratio of the ESU to EMU charge was approximately 3×10¹⁰ cm/s — the speed of light. This was no coincidence: Maxwell showed that light is an electromagnetic wave, and the unit ratio reflects the fundamental coupling between electric and magnetic fields. One of the greatest insights in physics history, hidden in a unit conversion.
Nanoampere – Frequently Asked Questions
Why does my microcontroller datasheet list nanoampere sleep currents?
Chip designers optimize deep-sleep modes to leak only 1–100 nA so a coin cell battery (225 mAh) can power the device for 5–10 years without replacement. Every nanoampere matters in IoT sensors deployed in remote locations where battery swaps are impractical or impossible.
Can you actually measure a single nanoampere of current?
Yes — picoammeters and source-measure units (SMUs) from Keithley or Keysight resolve currents down to 0.01 nA. The trick is shielding: at nanoampere levels, even humidity on a PCB trace or triboelectric effects from cable movement can introduce errors larger than the signal itself.
What biological processes produce nanoampere-level currents?
Individual ion channels in cell membranes pass about 2–10 picoamperes each, but clusters of channels in a patch-clamp experiment produce nanoampere signals. Electrochemical glucose sensors generate 50–500 nA proportional to blood sugar levels. Neural signal electrodes also detect nA-scale biocurrents.
How does nanoampere leakage current affect circuit design?
At nanoampere levels, leakage through PCB substrates, capacitor dielectrics, and transistor junctions becomes significant. High-impedance analog circuits must use guarded traces, Teflon standoffs, and low-leakage components. A fingerprint on a circuit board can introduce 1–10 nA of leakage from moisture absorption.
How many electrons per second is one nanoampere?
One nanoampere is about 6.24 billion electrons per second (6.24 × 10⁹ e/s). That sounds like a lot, but it is literally a billionth of the electron flow in a one-ampere current. Counting individual electrons at this rate is the basis of quantum current standards being developed at national metrology labs.