Biot to Nanoampere
Bi
nA
Conversion History
| Conversion | Reuse | Delete |
|---|---|---|
1 Bi (Biot) → 10000000000 nA (Nanoampere) Just now |
Quick Reference Table (Biot to Nanoampere)
| Biot (Bi) | 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 Biot (Bi)
The biot (Bi) equals exactly 10 amperes and is the base unit of electric current in the centimeter-gram-second electromagnetic (CGS-EMU) system. It is defined as the current in a pair of parallel conductors 1 cm apart that produces a force of 2 dynes per centimeter length — the CGS-EMU analogue of the SI ampere definition. In the CGS-EMU system the biot plays the same foundational role the ampere plays in SI: all other electromagnetic CGS-EMU units are derived from it. The biot is essentially obsolete in modern practice, but it appears in older physics literature and classical electrodynamics textbooks alongside the dyne, gauss, and oersted.
A current of 1 Bi equals 10 A — roughly the draw of a domestic electric kettle. References to the biot appear primarily in historical or theoretical contexts, not modern instrumentation.
Etymology: Named after Jean-Baptiste Biot (1774–1862), French physicist who, with Félix Savart, established the Biot–Savart law describing the magnetic field generated by a steady electric current.
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.
Biot – Frequently Asked Questions
Why is the biot exactly 10 amperes and not some other factor?
The CGS-EMU system defines its base units using centimeters, grams, and seconds instead of meters, kilograms, and seconds. The factor of 10 falls out naturally from the dimensional conversion: 1 Bi produces 2 dyn/cm force between wires 1 cm apart, and working through the CGS-to-SI conversion yields exactly 10 A.
Who was Jean-Baptiste Biot and why does he have a current unit?
Biot was a French physicist (1774–1862) who co-discovered the Biot–Savart law in 1820, describing how electric current generates a magnetic field in space. This was one of the foundational results linking electricity to magnetism. The CGS community honored him by naming their electromagnetic current unit after him.
Does anyone still use the biot in modern physics?
Essentially no. Even theorists who prefer CGS units typically use Gaussian units rather than pure CGS-EMU. The biot appears mainly in textbook conversion tables, historical physics papers, and graduate-level electrodynamics courses that teach multiple unit systems for pedagogical reasons.
How do I convert between biots and amperes?
Multiply biots by 10 to get amperes; divide amperes by 10 to get biots. A 30 A circuit carries 3 Bi; a 0.5 Bi current is 5 A. It is one of the simplest unit conversions in physics — just move the decimal point one place.
What is the Biot-Savart law and how does it relate to the biot unit?
The Biot-Savart law calculates the magnetic field produced by a small segment of current-carrying wire at any point in space. In CGS-EMU, it uses biots for current and gauss for the field. In SI it uses amperes and teslas. The law itself is fundamental — it is used to design MRI magnets, motors, and particle accelerators.
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.