Electrical Conductance Converter
Convert Siemens, Millisiemens, and Mhos.
Conductance vs Resistance
| Equation | Conductance (G) | Resistance (R) |
|---|---|---|
| Reciprocal | G = 1 / R | R = 1 / G |
| 1 Siemens (S) | 1 S | 1 Ω |
| 1 Millisiemens (mS) | 0.001 S | 1,000 Ω (1 kΩ) |
What is Conductance?
Electrical conductance is the measure of how easily electricity flows through a component. It is the wide-open reciprocal of resistance.
Unit Explanations
Siemens (S)
The SI unit of electric conductance. Named after Ernst Werner von Siemens. 1 S = 1 / Ω.
Mho (℧)
An older unit of conductance. "Mho" is "Ohm" spelled backwards. It is exactly equal to one Siemens.
Gemmho
A unit of conductance equal to 10⁻⁶ Siemens (or 1 microsiemens). Often used in water quality measurements for conductivity.
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The Flip Side of Resistance
If Resistance tells you how much a material opposes current, Conductance tells you how much it *welcomes* it. They are two sides of the same coin, with conductance being the mathematical reciprocal of resistance.
Beyond electronics, conductance is a critical measurement in water quality testing, chemical analysis, and biology. The conductivity of a solution directly indicates its dissolved mineral content (TDS).
The Siemens (S)
The Siemens (symbol: S) is the SI unit of conductance. It is equivalent to:
It is named after Werner von Siemens, a pioneer of the electrical industry. An older, informal name for this unit is the Mho (℧), which is simply "Ohm" spelled backwards—a delightfully intuitive choice!
Common Unit Prefixes
Conductivity in the Real World
Conductivity measurements are everywhere, from your aquarium to semiconductor fabs:
Used in semiconductor manufacturing; almost no ions.
Laboratory grade, very low mineral content.
Varies by region; minerals from pipes and source.
Very high due to dissolved salt (NaCl).
Metals have extremely high conductivity (Megasiemens per meter).
Body fluids are conductive due to dissolved salts.
💧 Conductivity in Water Quality
TDS (Total Dissolved Solids) meters often display values in ppm (parts per million), but they work by measuring conductivity (in µS/cm) and multiplying by a conversion factor (typically 0.5-0.7).
High conductivity in water isn't necessarily bad—it indicates minerals. But for applications like brewing beer, hydroponics, or aquariums, controlling conductivity is crucial for optimal results.
Frequently Asked Questions
What is Electrical Conductance?
Conductance (G) is a measure of how easily electric current flows through a material. It is the reciprocal (inverse) of resistance: G = 1/R. High conductance means low resistance, and vice versa. If resistance is like the narrowness of a pipe, conductance is like its width.
What is the difference between Conductance and Conductivity?
Conductance (G) is a property of a specific object (like a wire), measured in Siemens (S). Conductivity (σ) is a property of a material itself, measured in Siemens per meter (S/m). Conductivity tells you how well any piece of that material conducts, regardless of its size or shape.
What is a Siemens (S)?
The Siemens (S) is the SI derived unit of electrical conductance. It was named after German engineer Werner von Siemens. 1 Siemens = 1 Ampere / 1 Volt, which is also equal to 1 / 1 Ohm (1 Ω⁻¹).
What is a Mho (℧)?
The Mho is an older, informal unit of conductance. The name is simply 'Ohm' spelled backwards! Its symbol (℧) is an upside-down Omega (Ω). 1 Mho = 1 Siemens. While charmingly named, the Siemens is the official SI unit.
Why is Microsiemens (µS) used for water quality?
Pure water is a poor conductor. The conductivity of drinking water is typically in the range of 50-1500 µS/cm. Using microsiemens (1 µS = 0.000001 S) avoids awkward decimals. TDS (Total Dissolved Solids) meters often display µS/cm because dissolved minerals increase conductivity.
How do I convert Siemens to Ohms?
Since conductance is the inverse of resistance: Resistance (Ohms) = 1 / Conductance (Siemens). For example, a conductance of 0.01 S equals a resistance of 1 / 0.01 = 100 Ohms.
What factors affect the conductivity of a solution?
Three main factors: Ion Concentration (more dissolved salts = higher conductivity), Temperature (conductivity increases ~2% per °C rise), and Ion Type (H⁺ and OH⁻ ions are especially good conductors, making acids and bases highly conductive).
What is a typical conductivity for seawater vs. tap water?
Seawater has very high conductivity: ~50,000 µS/cm (50 mS/cm). Tap water varies from 50-1500 µS/cm. Distilled/Deionized water is around 0.5-5 µS/cm. Ultra-pure lab water can be less than 0.1 µS/cm.
Are Conductance and Admittance the same?
No. Conductance (G) is the real (resistive) part of Admittance (Y). Admittance (in AC circuits) is the complex inverse of Impedance, and includes both Conductance (G) and Susceptance (B): Y = G + jB. For purely resistive circuits, they are the same.
How do I measure conductance?
You can measure conductance indirectly by measuring resistance with an ohmmeter and calculating G = 1/R. For liquids, a conductivity meter (or TDS meter) with probes is used. These meters apply a voltage and measure the resulting current to calculate conductance.