Elektronika MK-52

The Elektronika MK-52 (Russian: Электро́ника МК-52) is an RPN-programmable calculator manufactured in the Soviet Union during the years 1983 to 1992. It belongs to the third generation of Soviet programmable calculators. Its original selling price was 115 rubles.

The functionality of the MK-52 is identical to that of the Elektronika MK-61, except that the MK-52 has an internal non-volatile EEPROM memory module for permanent data storage, a diagnostic slot, and a slot for ROM modules. The programming language and functionality of the MK-52 and MK-61 calculators were extensions of the earlier MK-54, B3-34, and B3-21 Elektronika calculators. The MK-52 is the only calculator known to have internal storage in the form of an EEPROM module.

As with many Soviet calculators, the MK-52 has a number of undocumented functions. In November 1988, the MK-52 went into space on the Soyuz TM-7 spacecraft, where it could have been used to calculate the trajectory of landing in the event of an onboard computer failure.

The MK-52 has 105 steps of volatile program memory, an internal EEPROM module (with 512 bytes of memory), and 15 7-byte registers. It uses four AA-size battery cells or can be plugged into a power adapter. It has a relatively dim, ten-digit (8 digit mantissa, 2 digit exponent) green vacuum fluorescent display. The MK-52 has an expansion port to which various ROM (Read-only memory) modules could be attached. Its system clock speed is approximately 75 kHz (derived from a phases generator chip), and it weighs approximately 400 grammes.

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