Gilbert to Coulomb per second
Gi
C/s
Conversion History
| Conversion | Reuse | Delete |
|---|---|---|
1 Gi (Gilbert) → 0.79577499999999604699 C/s (Coulomb per second) Just now |
Quick Reference Table (Gilbert to Coulomb per second)
| Gilbert (Gi) | Coulomb per second (C/s) |
|---|---|
| 0.1 | 0.0795774999999996047 |
| 0.5 | 0.39788749999999802349 |
| 1 | 0.79577499999999604699 |
| 2 | 1.59154999999999209398 |
| 5 | 3.97887499999998023494 |
| 10 | 7.95774999999996046988 |
| 100 | 79.57749999999960469877 |
About Gilbert (Gi)
The gilbert (Gi) equals 10/(4π) amperes — approximately 0.7958 A — and is the CGS-EMU unit of magnetomotive force (MMF) rather than a general-purpose current unit. In magnetic circuit analysis, MMF drives magnetic flux through a reluctance, analogously to how voltage drives current through resistance. A single-turn coil carrying 1 Gi of MMF passes 0.7958 A. In SI, magnetomotive force is measured in ampere-turns (A·T). The gilbert is obsolete but historically significant in transformer design, relay engineering, and magnetic circuit analysis dating from the late 19th century through the 1960s.
A relay coil requiring 2 Gi of MMF to actuate needs about 1.6 A·turn in SI terms. Vintage transformer and relay datasheets from the 1940s–1960s often specify MMF in gilberts.
Etymology: Named after William Gilbert (1544–1603), English physician and natural philosopher who authored De Magnete (1600), the first systematic scientific study of magnetism and electricity, establishing that the Earth itself acts as a giant magnet.
About Coulomb per second (C/s)
The coulomb per second (C/s) is a derived SI expression for electric current that makes the physical definition explicit: one ampere is exactly one coulomb of charge passing a point per second. The relationship I = Q/t links current (A), charge (C), and time (s). While C/s and A are numerically identical and dimensionally equivalent, the C/s form appears in physics textbooks and dimensional analyses where the derivation from charge and time is instructive rather than treating the ampere as primitive. In calculations tracking charge accumulation — capacitor discharge, electroplating, or battery coulomb-counting — expressing current in C/s clarifies the unit chain.
A capacitor delivering 1 C of charge over 1 second discharges at exactly 1 C/s = 1 A. A 500 mA USB charger transfers 0.5 C of charge each second.
Gilbert – Frequently Asked Questions
Why is the gilbert approximately 0.7958 amperes and not a round number?
The gilbert equals 10/(4π) amperes because the CGS-EMU system uses a different form of Ampere's law where the factor 4π appears explicitly rather than being absorbed into μ₀. This "unrationalised" form distributes 4π differently in the equations, producing the 1/(4π) factor when converting to SI's "rationalised" system.
What is magnetomotive force and how is it different from regular current?
MMF is the magnetic analogue of voltage — it drives flux through a magnetic circuit the way EMF drives current through an electrical circuit. For a coil, MMF = N × I (turns times current). A 100-turn coil carrying 1 A has 100 ampere-turns of MMF. In CGS, that same MMF would be about 125.7 gilberts.
Who was William Gilbert and why does he deserve a unit?
Gilbert (1544–1603) was physician to Queen Elizabeth I and author of De Magnete (1600), the first true scientific investigation of magnetism. He demonstrated that Earth is a magnet, distinguished magnetic from electrostatic attraction, and coined the word "electricus." He did all this 87 years before Newton's Principia — a genuine pioneer of experimental science.
Where would I find gilberts used today?
Practically nowhere in new designs. You might encounter gilberts in vintage relay and transformer datasheets from the 1940s–1960s, in older American and European magnetic component catalogs, or in classic electrical engineering textbooks. Any modern magnetic circuit analysis uses ampere-turns (A·T) for MMF.
How do I convert gilberts to ampere-turns?
Multiply gilberts by 10/(4π) ≈ 0.7958 to get ampere-turns. Wait — that is backwards. Multiply gilberts by 0.7958 to get amperes for a single-turn coil. For MMF conversion: 1 gilbert = 0.7958 ampere-turns. So a relay spec of 5 Gi needs about 4 ampere-turns to actuate — for instance, 4 turns at 1 A or 8 turns at 0.5 A.
Coulomb per second – Frequently Asked Questions
Why bother writing coulombs per second when it is just amperes?
In dimensional analysis and physics derivations, C/s makes the relationship between charge and current explicit. When you are computing how much silver an electroplating bath deposits (Faraday's law), writing current as C/s reminds you that charge = current × time, which directly gives the mass deposited.
How many electrons is one coulomb?
One coulomb is approximately 6.242 × 10¹⁸ electrons — about 6.2 quintillion. At 1 C/s (1 A), that many electrons pass a point in your wire every single second. A USB cable charging your phone at 2 A carries 12.5 quintillion electrons per second. The numbers are staggering but the charges are tiny.
Is coulombs per second used in any real-world instrument or specification?
Not directly — every instrument reads in amperes or milliamperes. But coulomb-counting battery fuel gauges internally track charge in coulombs by integrating current over time: ∫I dt. The C/s framing appears in battery management system firmware and electrochemistry literature where charge balance matters.
How does Faraday's law of electrolysis use coulombs to predict metal deposition?
Faraday discovered that the mass of metal deposited at an electrode is directly proportional to the total charge passed (in coulombs). For silver, 107.87 grams deposit per 96,485 C (one Faraday). So a 10 A electroplating bath running for 1 hour passes 36,000 C and deposits about 40 g of silver. Thinking in C/s makes the calculation: current × time × atomic weight / (valence × 96,485).
How does coulomb counting work in battery management systems?
A shunt resistor or Hall sensor continuously measures current flowing in and out of the battery. The BMS integrates this current over time (summing C/s × Δt) to track net charge. Drift and measurement errors accumulate, so smart BMS designs periodically recalibrate against voltage-based state-of-charge estimates.