Terminated: 2000
ELORG is short for Elektronorgtechnica (Всесою́зное Объедине́ние «Электро́норгтехника» in Russian). More information can be found on Wikipedia here (link validated 2025-12-06).
This calculator was in production for quite a long time. The website elektronika.su referred to below lists the period as 1982 to 2000. The SOVIET DIGITAL ELECTRONICS MUSEUM (link validated 2025-12-06) lists the period as 1984 to 1991. According to this specimen’s back this particular one was fabricated in 1985 in the USSR.
It is an 8-digit scientific calculator and it supports a 2-digit exponent. It has all the common scientific functions and has a statistical mode.
Likewise to most of the early CASIO scientific calculators, this calculator uses one and the same key for both the constant π as well as exponents. This works as follows. When you first enter digits, the EXP key will enable you to enter the exponent, otherwise it will enter the constant π.
Basic operations can be repeated by pressing the operator twice and then repeatedly pressing the = key. For additions and subtractions it will repeatedly add or subtract the first operand.
The ↔ operation swaps the operands of a calculation, commonly indicated as x↔y on other calculators.
Note the styled "0", "6", "8" and "9" on its keypad.
As it uses a 2-digit exponent the biggest factorial it can calculate is 69!. Fun fact: it takes a long time to error out on factorials of 70 up to 99. The factorial of 100 errors out immediately. It is probably easier to check for numbers greater or equal than 100 than it is to check for numbers greater than 69.
The yx operator can only accept non-negative values for y. One can, for instance, not calculate (-3)2 using yx. This is probably due to it internally using this formula to calculate powers:
yx = e(x · ln y)
This works nicely for positive values of x but will result in an
error when x is zero or less. Not a big problem because powers of negavive
numbers behave counter intuitive anyway (producing non-complex results
only for integer values of y or fractional values of y with an odd
denominator).
More information on the ELEKTRONIKA-51 can be read on the elektronika.su website here (link validated 2025-12-06).
According to its manual it needs a ДMЛ-120 (link validated 2025-12-06) Russian lithium element to operate, but it also runs fine on a CR2025. According to its manual it can run over 1000 hours with continuous use on one ДMЛ-120.
The ELORG·51 shown here came with an English as well as a Dutch manual. The English manual looks like it originally came with the calculator, the Dutch manual looks to be translated specifically for the Dutch market.
Due to its very reflective front it was difficult to make a proper scan of this calculator.
All in all an easy to use scientific calculator.