Elektronika B3-21

An Elektronika B3-21.

Elektronika B3-21 (Cyrillic: Электроника Б3-21) was the first Soviet programmable calculator. It was released in 1977 and was sold initially for 350 rubles (190 in 1980-81, and just 80 rubles at late 1981). For comparison, 120 rubles was a monthly engineer's salary. The production was stopped in 1982 because of introduction of more advanced Elektronika B3-34.

Features

• program memory - 60 steps (no ROM, the code is lost after shut down);
• data memory - 2 operating registers, 7 additional directly addressed registers, 6 loop stack registers;
• accuracy - 8 Significand digits (7 if the value includes decimal dot), 2 exponent digits;
• operations - besides 4 arithmetic ones there were 1/x, x², x^y, sqrt(x), exp(x), ln(x), sin(x), cos(x);
• conditional and unconditional branching, subroutine calls;
• speed - 3-5 operations (program steps) per second on average (with x^y taking the longest time of about 3 seconds);
• powered by disc accumulators (4 * 1.25 Volts) or charger.

Derived models

• Elektronika MK-46 - desktop version, differed also by having 66 steps program memory, digital inputs for connecting external devices and output, e.g. for printer (along with functionality to control them);
• Elektronika MK-64 (and later Elektronika MS-1103) - the same as MK-46 but with internal ADC installed so that several analog inputs could be controlled (measurements from -9.99 to 9.99 Volts with accuracy of 0.02 Volts);
• Elektronika MK-47 - rare handheld clone of B3-21, allowing to store programs to magnetic memory cards.

External links

• - Detailed description of B3-21 at the online calculator collection site by Viktor T. Toth