Ohm Symbol Ω Copy & Paste: Resistance Unit, Math & Keyboard
The ohm symbol (Ω) represents electrical resistance in physics and engineering. Named after Georg Simon Ohm, it appears on resistors, circuit diagrams, physics textbooks, and multimeters worldwide. Every variation is below, ready to copy.
All Ohm / Omega Symbols
| Symbol | Name | Unicode | Copy |
|---|---|---|---|
| Ω | Ohm (Capital Omega) | U+2126 | Ω |
| ω | Lowercase Omega | U+03C9 | ω |
| ℧ | Mho (Inverted Omega) | U+2127 | ℧ |
What Does the Ohm Symbol Mean?
The ohm (Ω) is the SI unit of electrical resistance. One ohm equals the resistance between two points of a conductor when a constant potential difference of one volt applied to these points produces a current of one ampere. The formula is simple: R = V / I, where R is resistance in ohms, V is voltage, and I is current.
Ohm in Everyday Electronics
- Resistors: Every resistor has an ohm rating. A 4.7kΩ resistor limits current in a circuit.
- Speakers: Most speakers are rated at 4Ω, 8Ω, or 16Ω. Lower impedance means more power drawn from the amplifier.
- Multimeters: Digital multimeters measure resistance in ohms, kilohms (kΩ), and megohms (MΩ).
- Circuit design: Ohm's Law (V = IR) is the foundation of all circuit analysis.
Ohm vs Omega: What is the Difference?
Technically, the ohm symbol (U+2126) and the Greek capital omega (U+03A9) look identical. Unicode treats them as the same character for rendering purposes. The ohm sign is canonically equivalent to the Greek capital letter omega. In practice, they are interchangeable — type either one and it will display as Ω.
How to Type the Ohm Symbol
Windows
- Hold Alt and type 234 on the numeric keypad
- Or use Character Map: search for "ohm" or "omega"
- Microsoft Word: type 2126 then press Alt+X
Mac
- Press Option + Z to type Ω
- Or use Character Viewer: Control+Command+Space, search "omega"
Linux
- Press Ctrl+Shift+U, type 03A9, press Enter
- Or use the Character Map application
iPhone & Android
- iPhone: Add Greek keyboard in Settings, then tap Ω. Or copy from this page.
- Android: Long-press the O key on Gboard, or add Greek keyboard. Or just copy from above.
LaTeX and HTML Codes
| Format | Code | Result |
|---|---|---|
| LaTeX | \Omega | Ω |
| LaTeX (lowercase) | \omega | ω |
| HTML Entity | Ω | Ω |
| HTML Decimal | Ω | Ω |
| HTML Hex | Ω | Ω |
| CSS Content | \03A9 | Ω |
Common Ohm Values in Electronics
| Value | Written As | Common Use |
|---|---|---|
| 1 Ω | 1 ohm | Current sensing |
| 100 Ω | 100 ohms | Signal termination |
| 1,000 Ω | 1 kΩ | LED current limiting |
| 10,000 Ω | 10 kΩ | Pull-up/pull-down resistors |
| 1,000,000 Ω | 1 MΩ | High-impedance inputs |
Fun Facts About the Ohm Symbol
- Georg Simon Ohm published his law in 1827, but the unit was not officially named until 1861.
- The inverted omega (℧) represents mho, the unit of conductance. It is literally an upside-down Ω. Today, conductance is measured in siemens (S), but the mho symbol persists in older texts.
- In video games and pop culture, the omega symbol often represents "the end" or final boss, since omega is the last letter of the Greek alphabet.
- Resistance color bands on resistors encode the ohm value — a 4.7kΩ resistor has yellow, violet, and red bands.
Related Symbols
- Omega (Ω): The Greek letter that doubles as the ohm symbol
- Volt (V): Unit of electric potential
- Ampere (A): Unit of electric current
- Watt (W): Unit of power, calculated as V times A
- Siemens (S): Unit of conductance, the reciprocal of ohm (1/Ω)