CGS e.m. unit to Nanoampere
CGS EMU
nA
Conversion History
| Conversion | Reuse | Delete |
|---|---|---|
1 CGS EMU (CGS e.m. unit) → 10000000000 nA (Nanoampere) Just now |
Quick Reference Table (CGS e.m. unit to Nanoampere)
| CGS e.m. unit (CGS 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 CGS e.m. unit (CGS EMU)
The CGS electromagnetic unit (CGS e.m. unit) of current equals exactly 10 amperes, numerically identical to the biot and the EMU of current — all three are names for the same quantity within the CGS-EMU system. The term "CGS e.m. unit" is used explicitly when distinguishing the electromagnetic subsystem from the electrostatic (ESU) or Gaussian subsystems within CGS. In the CGS-EMU framework, resistance, capacitance, and inductance take unfamiliar dimensions compared to SI; the system is now of historical and theoretical interest only. Modern engineering and science universally use SI.
1 CGS e.m. unit = 10 A. A 100 A industrial busbar carries 10 CGS e.m. units. The designation appears only in pre-1960 electrical engineering 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.
CGS e.m. unit – Frequently Asked Questions
Why were "absolute" and "practical" electrical units different in the 19th century?
The CGS e.m. unit of current (10 A) was inconveniently large for everyday lab work, while the CGS e.m. unit of resistance (the abohm, 10⁻⁹ Ω) was absurdly small. Physicists created "practical" units — the ampere, volt, and ohm — as decimal multiples that gave human-scale numbers. The ampere was set at 0.1 abampere. These practical units eventually became SI, while the "absolute" CGS units became historical footnotes.
Why does the CGS system have three different subsystems for the same physics?
In the 19th century, electricity and magnetism were treated as partially separate phenomena, leading to separate "natural" unit choices. The EMU system normalized magnetic permeability to 1; the ESU system normalized electric permittivity to 1; the Gaussian system mixed both. Once Maxwell unified electromagnetism, this fragmentation became unnecessary — but the systems persisted in literature for a century.
How did physicists handle the factor-of-10 difference between CGS e.m. units and practical amperes?
They introduced "practical" units — the ampere, volt, and ohm — as decimal multiples of CGS-EMU quantities. The ampere was defined as 0.1 abampere (CGS e.m. unit). This practical system eventually became SI, while the "absolute" CGS units faded. The factor of 10 was chosen for human-scale convenience.
What other CGS electromagnetic units still show up in modern contexts?
The gauss (magnetic flux density, = 10⁻⁴ tesla) remains surprisingly common — refrigerator magnets are rated in gauss, and MRI field strengths are often quoted in both tesla and gauss. The oersted (magnetic field strength) appears in materials science. These CGS-EMU holdouts persist because their numerical values are more convenient for everyday magnets.
When did the transition from CGS to SI happen in practice?
The SI was officially adopted in 1960, but the transition took decades. Most physics journals required SI by the 1970s, though astrophysics and plasma physics held onto Gaussian CGS into the 2000s. Some subfields never fully switched — you can still find new papers using gauss and oersted alongside tesla and A/m.
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.