Электроника C3-22 – an ordinary calculator with an extraordinary integrated circuit

In the early 1970s, engineers from the Leningrad Electronic Instrumentation Association “Svetlana” (Светлана) began work on the next calculator, the Электроника C3-07 (Elektronika C3-07). This device was a rather simple design with only fifteen keys, meaning that some functions had to be assigned to the same button. Such a solution was quite problematic, more than once there were mistakes, and also just typing in the right sequence took quite a long time. In the successor to the C3-07, the designers had to eliminate these inconveniences.