ESU of current to Nanoampere
ESU
nA
Conversion History
| Conversion | Reuse | Delete |
|---|---|---|
1 ESU (ESU of current) → 0.3335641 nA (Nanoampere) Just now · Rounding: Up to 8 significant figures | Recalculate this conversion using your current rounding settings. |
Quick Reference Table (ESU of current to Nanoampere)
| ESU of current (ESU) | Nanoampere (nA) |
|---|---|
| 1 | 0.3335641 |
| 10 | 3.335641 |
| 100 | 33.35641 |
| 1,000,000 | 333,564.1 |
| 1,000,000,000 | 333,564,100 |
| 3,000,000,000 | 1,000,692,300 |
Results rounded to a maximum of 8 significant figures
About ESU of current (ESU)
The electrostatic unit of current (ESU, also called the statampere) equals approximately 3.335640952×10⁻¹⁰ amperes under the traditional CGS-to-SI mapping used by this converter. It is the current unit of the CGS electrostatic system (CGS-ESU), in which Coulomb's law is written without a permittivity constant and electric charge is measured in statcoulombs (franklins). One statampere is the flow of one statcoulomb per second. The traditional mapping is 1 A = (c/10) statamperes, using the numerical speed of light c = 29,979,245,800 in cm/s, so 1 A maps to 2,997,924,580 statamperes. This is a conventional mapping, not a claim of an exact physical conversion to the post-2019 SI. The CGS-ESU system was used in early electrostatics and vacuum tube physics but is obsolete in applied engineering.
1 ESU of current ≈ 3.336×10⁻¹⁰ A — an extraordinarily small current. One ordinary ampere equals approximately 3×10⁹ ESU.
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.
ESU of current – Frequently Asked Questions
Why is the ESU of current so absurdly small compared to an ampere?
The ESU system was designed to make Coulomb's electrostatic law simple (no constants), which means its charge unit (the statcoulomb) is tiny relative to the coulomb. Since current is charge per time, the statampere inherits that smallness. Under the traditional mapping used here, one ampere maps to 2,997,924,580 statamperes — the numerical speed of light in cm/s divided by 10. In the reverse direction, multiply the statampere value by 10/c, or divide by 2,997,924,580, to obtain amperes.
What is a statampere and is it the same as an ESU of current?
Yes. Statampere, ESU of current, CGS electrostatic current, franklin per second and Gaussian current share the same current scale. This converter uses the same traditional mapping for all five names: 1 A maps to 2,997,924,580 statamperes. "Statampere" is the named form; "ESU of current" is the descriptive form. The "stat-" prefix comes from "electrostatic," just as the "ab-" prefix in the EMU system comes from "absolute."
Did the 2019 SI redefinition change the statampere?
No. The statampere remains one statcoulomb per second in the CGS system. What changed was the SI ampere: in 2019 it was redefined by fixing the elementary charge, replacing its earlier force-based definition. Vacuum permeability and permittivity are consequently no longer exact SI constants, so physical conversions between CGS electrical units and modern SI involve measured values and uncertainty. This converter retains the pre-2019 mapping of 1 A to 2,997,924,580 statamperes for consistent reference conversions; it does not apply modern measured corrections.
What role did the ESU system play in the discovery that light is electromagnetic?
When Weber and Kohlrausch measured the ratio of ESU to EMU charge in 1856, they got a number suspiciously close to the speed of light — about 3×10¹⁰ cm/s. Maxwell realized this was no coincidence: it meant electromagnetic disturbances propagate at light speed, proving light itself is an electromagnetic wave. A unit conversion exercise led to one of the greatest discoveries in physics.
What practical problem did the ESU system solve for 19th-century telegraph engineers?
Telegraph cables behaved like long capacitors — charge stored along the line distorted signals over transatlantic distances. The ESU system, built around Coulomb's law, made capacitance calculations straightforward: no permittivity constants, just geometry and charge. William Thomson (Lord Kelvin) used ESU-based analysis to diagnose and fix signal distortion on the first transatlantic telegraph cables in the 1860s.
Why were electrostatic and electromagnetic measurements historically done in separate labs?
Electrostatic experiments (rubbing rods, Leyden jars, spark gaps) involved high voltages and tiny charges, while electromagnetic work (coils, galvanometers, telegraph lines) involved low voltages and large currents. The equipment, techniques, and even the physicists were different. Each community built units natural to their measurements — ESU for electrostatics, EMU for electromagnetics — and it took decades after Maxwell to unify them into one coherent SI framework.
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.