**Eelisarvurida** ehk **eelisarvude rida** on matemaatiliselt korrastatud arvujada, mida kasutatakse tehnikas toote mingi parameetri arvväärtuste unifitseerimiseks (ühtsustamiseks).

R-eelisarvud
------------

Eelisarvude rea loomisel on enamasti aluseks geomeetriline jada, s.o jada, mille iga element on saadud eelmise elemendi korrutamisel selle jada jaoks kindla teguriga (kordajaga). Niisugustest ridadest on tuntuim masinaehituses kasutatav eelisarvurida, mille teguriks on arvu 10 juur ja tähiseks R (Prantsuse inseneri Charles Renard`i auks, kes aastail 1877‒1879 ühtsustas aerostaadi kinnitusköite nomenklatuuri).

R-rea elemendid avalduvad kujul

{\displaystyle a\_{n}=a\_{n-1}\cdot {\sqrt[{m}]{10}}.}
Standarditud on neli põhirida vastavalt juurija *m* väärtustele 5,10, 20 ja 40 (rea tähises olev arv väljendab ühtlasi rea elementide arvu):

* R5 ‒ reategur {\displaystyle {\sqrt[{5}]{10}}\approx 1,6}
* R10 ‒ reategur {\displaystyle {\sqrt[{10}]{10}}\approx 1,25}
* R20 ‒ reategur {\displaystyle {\sqrt[{20}]{10}}\approx 1,12}
* R40 ‒ reategur {\displaystyle {\sqrt[{40}]{10}}\approx 1,06}

Eelisarvude korrutis ja jagatis ning täisarvulised astmed on samuti eelisarvud. Vajadust mööda võib reaväärtusi korrutada teguriga 10*n* (*n* võib olla positiivne või negatiivne). Ridade elementide standardväärtused on vähemal või suuremal määral ümardatud.

R-ridu määravad standardid:

* ISO 3:1973, *Preferred Numbers – Series of Preferred Numbers*.
* ISO 17:1973, *Guide to the Use of Preferred Numbers and of Series of Preferred Numbers*.
* ISO 497:1973, *Guide to the Choice of Series of Preferred Numbers and of Series Containing More Rounded Values of Preferred Numbers*.

R-eelisarvude väärtused
-----------------------

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| 

| Veidi ümardatud |
| --- |
| R5 | R10 | R20 | R40 |
| 1,00 | 1,00 | 1,00 | 1,00 |
| 1,06 |
| 1,12 | 1,12 |
| 1,18 |
| 1,25 | 1,25 | 1,25 |
| 1,32 |
| 1,40 | 1,40 |
| 1,50 |
| 1,60 | 1,60 | 1,60 | 1,60 |
| 1,70 |
| 1,80 | 1,80 |
| 1,90 |
| 2,00 | 2,00 | 2,00 |
| 2,12 |
| 2,24 | 2,24 |
| 2,36 |
| 2,50 | 2,50 | 2,50 | 2,50 |
| 2,65 |
| 2,80 | 2,80 |
| 3,00 |
| 3,15 | 3,15 | 3,15 |
| 3,35 |
| 3,55 | 3,55 |
| 3,75 |
| 4,00 | 4,00 | 4,00 | 4,00 |
| 4,25 |
| 4,50 | 4,50 |
| 4,75 |
| 5,00 | 5,00 | 5,00 |
| 5,30 |
| 5,60 | 5,60 |
| 6,00 |
| 6,30 | 6,30 | 6,30 | 6,30 |
| 6,70 |
| 7,10 | 7,10 |
| 7,50 |
| 8,00 | 8,00 | 8,00 |
| 8,50 |
| 9,00 | 9,00 |
| 9,50 |
| 10,0 | 10,0 | 10,0 | 10,0 |

 | 

| Ümardatud |
| --- |
| R'10 | R'20 | R'40 |
| 1,00 | 1,00 | 1,00 |
| 1,05 |
| 1,12 | 1,12 |
| 1,20 |
| 1,25 | 1,25 | 1,25 |
| 1,30 |
| 1,40 | 1,40 |
| 1,50 |
| 1,60 | 1,60 | 1,60 |
| 1,70 |
| 1,80 | 1,80 |
| 1,90 |
| 2,00 | 2,00 | 2,00 |
| 2,10 |
| 2,20 | 2,20 |
| 2,40 |
| 2,50 | 2,50 | 2,50 |
| 2,60 |
| 2,80 | 2,80 |
| 3,00 |
| 3,20 | 3,20 | 3,20 |
| 3,40 |
| 3,60 | 3,60 |
| 3,80 |
| 4,00 | 4,00 | 4,00 |
| 4,20 |
| 4,50 | 4,50 |
| 4,80 |
| 5,00 | 5,00 | 5,00 |
| 5,30 |
| 5,60 | 5,60 |
| 6,00 |
| 6,30 | 6,30 | 6,30 |
| 6,70 |
| 7,10 | 7,10 |
| 7,50 |
| 8,00 | 8,00 | 8,00 |
| 8,50 |
| 9,00 | 9,00 |
| 9,50 |
| 10,0 | 10,0 | 10,0 |

 | 

| Tugevalt ümardatud |
| --- |
| R′′5 | R′′10 | R′′20 |
| 1,0 | 1,0 | 1,0 |
| 1,1 |
| 1,2 | 1,2 |
| 1,4 |
| 1,5 | 1,5 | 1,6 |
| 1,8 |
| 2,0 | 2,0 |
| 2,2 |
| 2,5 | 2,5 | 2,5 |
| 2,8 |
| 3,0 | 3,0 |
| 3,5 |
| 4,0 | 4,0 | 4,0 |
| 4,5 |
| 5,0 | 5,0 |
| 5,5 |
| 6,0 | 6,0 | 6,0 |
| 7,0 |
| 8,0 | 8,0 |
| 9,0 |
| 10 | 10 | 10 |

 |

E-read
------

 *Pikemalt artiklis  E-rida*
Elektroonikas määratakse passiivelementide tunnussuuruste nimiväärtused ‒ takistite takistus, kondensaatorite mahtuvus ja induktiivelementide induktiivsus ‒ E-ridadega. Need on samuti geomeetrilised jadad, mille teguriks on arvu 10 juur, kuid erinevalt R-ridadest avaldub rea teguri juurija *m* kujul 3 • 2*n*, seega saab *m* väärtus olla 3, 6, 12, 24, … .

Muid eelisarvuridu
------------------

Arvutitehnikas on kasutusel mälumahtude rida arvu 2 astmetena: 20 = 1, 21 = 2, 22 = 4, 23 = 8, 24 = 16, 25 = 32, 26 = 64, 27 = 128, 28 = 256, 29 = 512, 210 = 1024 (≈ 1×103, 2, 4, …)

Optikariista objektiivi avaarvude geomeetrilise jada teguriks on √2. Avaarvude rea väärtusi (ümardatult):   

0,7 ‒ 1 ‒ 1,4 ‒ 2 ‒ 2,8 ‒ 4 ‒ 5,6 ‒ 8 ‒ 11 ‒ 16 ‒ 22 ‒ 32 …

Teguriga √2 on määratud ka paberi A-rea DIN-formaadid (standard DIN 476 aastast 1922, vastav Euroopa standard EN ISO 216). Baasformaadi A0 pindala on 1 m2 ja küljepikkuste suhe 1 : √2, seega formaat 841 × 1189 mm. Igal järgmisel formaadil on üks küljepikkus 2 korda väiksem (pindala pool eelmisest); küljepikkuste suhe on kõigil formaatidel √2.

| A0 | A1 | A2 | A3 | A4 | A5 | A6 | A7 |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 841 ×1189 mm | 841 × 594 mm | 420 × 594 mm | 420 × 297 mm | 210 × 297 mm | 210 ×148 mm | 105 × 148 mm | 105 × 74 mm |

Välislingid
-----------

* Eelisarvude read
* 

| * v
* r
ISO standardid |
| --- |
| 1–9999 | 
3 • 216 • 261 • 262 • 269 • 639(-1, -2, -3) • 1538 • 1989 • 2108 • 3166(-1, -2:EE, -2:US) • 3297 • 4217 • 7089 • 7098 • 7498 • 8601 • 8879 • 9000 • 9001 • 9075 • 9293 • 9594 • 9945 |
| 10000–19999 | 
10206 • 13211 • 13616 • 14396 • 14496(-10) • 15445 • 16262 • 18004 • 19501 • 19505 • 19510 |
| 20000+ | 
26300 • 26324 • ISO 27000 • 32000 |