Inductance is a vital concept to understand in electronics and engineering. It can be described as an electrical conductor’s property that quantifies its ability to store energy in a magnetic field when an electric current flows through it.
What Are the Commonly Used Units of Inductance?
The base unit for measuring inductance in the International System of Units (SI) is the henry (H). It is named after Joseph Henry (1797-1878), the American physicist largely known for having discovered self-inductance.
One henry is the inductance of a circuit in which a change of current of one ampere per second induces a voltage of a single volt.
Henry is the standard unit of inductance. It sees frequent use in large-scale applications such as power transformers or motors, where inductance values are typically high.
However, the henry also has various submultiples, such as:
- Millihenry (mH), which is one-thousandth of a henry. It is often used in applications characterised by moderate inductance values, such as power supplies, filters, and audio circuits.
- Microhenry (µH), which is one-millionth of a henry. This unit is commonly used in such applications as small inductors and radio frequency (RF) circuits.
- Nanohenry (nH), which is one-billionth of a henry. It is typically very high-frequency circuits in which this unit is used, such as RF antennas, microwave circuits, or integrated circuits.
Why Might an Engineer Need to Convert Between Inductance Values?
There are many reasons why those operating in the electronics and engineering fields may need to convert between the aforementioned units of inductance from time to time.
For example, when it comes to the labelling of inductance values on inductors and other components, the exact units stated may vary from one item to the next. So, it might be necessary for an engineer to convert values to match datasheets, design requirements, or component availability.
Knowing how to convert between different units of inductance can also bring greater ease and speed to such processes as circuit design and analysis, component selection and sourcing, and communication and documentation.
How Can You Convert Between These Inductance Units?
Here is a summary of how the units of inductance we have mentioned in this article relate to each other. Making a note of these will help you ensure accurate conversions every time:
- 1 H = 1,000 mH = 1,000,000 µH = 1,000,000,000 nH
- 1 mH = 0.001 H = 1,000 µH = 1,000,000 nH
- 1 µH = 0.000001 H = 0.001 mH = 1,000 nH
- 1 nH = 0.000000001 H = 0.000001 mH = 0.001 µH
So, here are the broad rules for how to do the conversions:
- If you’re looking to convert to smaller units, multiply by 1,000 for each step down (from H to mH to µH to nH)
- If you’re looking to convert to larger units, divide by 1,000 for each step up (from nH to µH to mH to H)
As far as the essentials of inductance value conversion are concerned, that’s more-or-less it.
Well, we do have one more piece of advice to give: even if you’re confident in performing manual calculations using the conversion factors above, do make sure you also use an inductance conversion calculator for electronics work where a high level of precision is needed. This will enable you to verify the accuracy of the results gained from your manual workings-out.
