ELKA () is a

Bulgaria Bulgaria, officially the Republic of Bulgaria, is a country in Southeast Europe. It is situated on the eastern portion of the Balkans directly south of the Danube river and west of the Black Sea. Bulgaria is bordered by Greece and Turkey t ...

n brand of

electronic calculator An electronic calculator is typically a portable Electronics, electronic device used to perform calculations, ranging from basic arithmetic to complex mathematics. The first solid-state electronic calculator was created in the early 1960s. ...

, developed by the and built at the ''Elektronika'' plant in

Sofia Sofia is the Capital city, capital and List of cities and towns in Bulgaria, largest city of Bulgaria. It is situated in the Sofia Valley at the foot of the Vitosha mountain, in the western part of the country. The city is built west of the Is ...

. The name is a contraction of ''електронен калкулатор'', or "electronic calculator", and the word ''elka'' has, by extension, become the generic name for a calculator in Bulgaria. The first model, the ELKA 6521, was introduced in 1965, shipped from 1966, and used germanium

transistors A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch electrical signals and electric power, power. It is one of the basic building blocks of modern electronics. It is composed of semicondu ...

and a

nixie tube A Nixie tube ( ), or cold cathode display, is an electronics, electronic device used for display device, displaying numerals or other information using glow discharge. The glass tube contains a wire-mesh anode and multiple cathodes, shaped like ...

display.The ELKA Bulgarian electronic calculators
''Clockwiser''. Retrieved Oct 2013. It weighed 16 kg and although some Bulgarian authors claim that it was the first calculator in the world to include a one-key

square root In mathematics, a square root of a number is a number such that y^2 = x; in other words, a number whose ''square'' (the result of multiplying the number by itself, or y \cdot y) is . For example, 4 and −4 are square roots of 16 because 4 ...

function it was preceded in this respect by several models from American and Japanese manufacturers. Its developers—Lyubomir Antonov, Petar Popov and Stefan Angelov, were the first scientists in the field of electronics to win the highest honour in

at the time, the Order of Georgi Dimitrov. Later, the models ELKA 22 (again, with a nixie tube display) and ELKA 25, (with a built-in printer) were developed. These models had a plastic case and were based again on discrete technology, their numerous phenolic boards being populated with hundreds of transistors, diodes and resistors, plus a magnetic-core memory. Their experimental production began in 1966.ELKA 22, Bulgarian Calculator
, ''Soviet digital calculators collection, www.rk86.com/frolov/''. Retrieved Oct 2013. These two models proved successful and in 1967 their serial production began in earnest by the Factory for Organizational Technology in

Silistra Silistra ( ; ; or ) is a town in Northeastern Bulgaria. The town lies on the southern bank of the lower Danube river, and is also the part of the Romanian border where it stops following the Danube. Silistra is the administrative center of the ...

. In 1969, the Scientific research, study and design institute for electronic calculators was founded specifically for the design of calculators. In 1972 this developed the lighter and more portable, but still relatively large calculator models ELKA 40 and ELKA 42 built around integrated circuits (medium-scale integration). These had again nixie tube displays. Later models in the 1970s were the ELKA 50 and ELKA 1300, which had a similar outward appearance and used vacuum-fluorescent tube displays and relatively expensive but very reliable reed-switch keyboards. Meanwhile, the ELKA 77 was the first electronic

cash register A cash register, sometimes called a till or automated money handling system, is a mechanical or electronic device for registering and calculating transactions at a point of sale. It is usually attached to a Cash register#Cash drawer, drawer fo ...

. The first pocket model was the ELKA 101, introduced in 1974. This was the first in a large series, including the scientific ELKA 135. Other models in the 100 series included the ELKA 103, 105, 131 and 130M. These were all designed with export in mind, so all writing on them is in

Latin script The Latin script, also known as the Roman script, is a writing system based on the letters of the classical Latin alphabet, derived from a form of the Greek alphabet which was in use in the ancient Greek city of Cumae in Magna Graecia. The Gree ...

. The 100 series came in three bright colours—orange, green, and yellow, and their displays could be either red or green. ELKA 101 description
''Vintage Calculators''. Retrieved Oct 2013. As of 2013 the factory in Silistra, now named "Orgtehnika", still produces mostly vending oriented machines branded ELKA: cash registers, electronic scales, taxi meters, etc.ELKA Products
''orgatehnika.bg''. Retrieved Aug 2017.

References

{{reflist, 30em Electronic calculators by company Goods manufactured in Bulgaria

See also

References