Elka 22
The Elka 22 was the second Bulgarian electronic calculator; it was released in 1966 and its serial production began in 1967 in the town of Silistra. Weighing 8.5 kilograms, the Elka 22 has 3 registers and operates with 12 decimal digits. Addition speed is 0.3 seconds per operation, and division speed is 0.5 seconds. Its power consumption is 35 watts.
This calculator has a plastic case, a nixie tube display and its technology is based on numerous phenol boards populated with hundreds of discrete transistors, diodes and resistors, not unlike other calculator models developed around the mid-1960s. The machine used a magnetic-core memory. It was widely used in Bulgaria and the other Eastern bloc countries until around 1980, long after its technology had become obsolete in the West around 1970.
