The diode symbol / one symbol, used everywhere
Twelve bars. Each one is a sentence.
The arrow was not drawn. It was typed. Every bar is one line of the Faraday arrow, as long as the line itself.
What is in it
Eight features
Nothing in the mark is decoration. Each part comes from the text, the history or the product.
- 1
The words make the shape
Set in a monospace font, every character has the same width. So the length of each bar is the number of characters in its line. Nobody drew the arrowhead. The sentences grow and shrink, and the arrow appears.
- 2
The head is what is missing
No chip. No battery. No power supply. No firmware to flash. No password to steal. No speed limit. Six absences, in cream. A passive diode is defined by what it does not have.
- 3
It ends on the direction
The last two lines are "Data leaves." and "Out." The shortest bar of the arrow is the word Out.
- 4
The shaft is the history
Three amber bars carry the physics: Faraday saw a magnet twist light in glass on 13 September 1845, and Lord Rayleigh made it a one-way door in 1885. The two longest bars are the two lines that carry the references.
- 5
One blue bar
The fourth shaft bar is BM Global, the newest line, carried by the three lines of physics above it. It is the only blue in the mark.
- 6
It points one way
There is no second head and no way back. The symbol of a one-way device is itself one way. One way by construction, not by configuration.
- 7
It is built, not drawn
A short script turns the twelve line lengths into twelve rounded bars. Every copy, from a browser tab to a poster, has the same geometry.
- 8
The colours of the arrow
Navy, cream, amber and blue are the colours of the approved Faraday arrow. The mark and the arrow are one family: the arrow is the mark, read aloud.
Anatomy
Bar by bar
Bar length and indent in characters. One character is half a unit, so a 53-character bar is 26.5 units long.
| Bar | Part | Length | Indent | Line of the Faraday arrow |
|---|---|---|---|---|
| 1 | Head | 8 | 26 | No chip. |
| 2 | Head | 11 | 26 | No battery. |
| 3 | Head | 16 | 26 | No power supply. |
| 4 | Head | 21 | 26 | No firmware to flash. |
| 5 | Shaft | 49 | 0 | Michael Faraday saw a magnet twist light in glass |
| 6 | Shaft | 53 | 0 | on 13 September 1845.¹ In 1885, Lord Rayleigh made it |
| 7 | Shaft | 53 | 0 | a one-way door.² Since then, it never needed a patch. |
| 8 | Shaft | 49 | 0 | And now, BM Global brings it to guard your plant. |
| 9 | Head | 21 | 26 | No password to steal. |
| 10 | Head | 15 | 26 | No speed limit. |
| 11 | Head | 12 | 26 | Data leaves. |
| 12 | Head | 4 | 26 | Out. |
Geometry
The rules
- Bars
- 12, one per line. 4 head, 4 shaft, 4 head.
- Head
- 8, 11, 16, 21 and 21, 15, 12, 4 characters, indent 26
- Shaft
- 49, 53, 53, 49 characters, indent 0
- Scale
- 0.5 unit per character
- Bar height
- 0.9 unit, fully rounded ends
- Row pitch
- 1.6 units
- Box
- 26.5 by 19.2 units
Colour
Four colours
- Navy#0B1628Ground of the dark version
- Cream#E8DCC4Head on dark
- Ink blue#283A5AHead on light
- Amber#F2A93BFaraday and Rayleigh
- Blue#60B2F0BM Global
Use
Light, dark and small
The same twelve bars at every size. On dark ground the head turns cream.
On this site it is the brand in the header, the browser tab icon, the diode on the one-way lane on the home page, and dd04 and dd05 in the Overview drawing.
Sources
The two dates
Faraday discovered the effect. Rayleigh made the one-way arrangement.
- M. Faraday, Diary, 13 September 1845, paragraph 7504. http://faradaysdiary.com/ws3/faraday.pdf. Experimental Researches in Electricity, Nineteenth Series, Phil. Trans. R. Soc. 136, 1–20 (1846). https://archive.org/details/philtrans00754832
- Lord Rayleigh, Phil. Trans. R. Soc. 176, 343 (1885). https://www.nature.com/articles/064577e0 and https://ar5iv.labs.arxiv.org/html/2104.06530