Virtual Museum > The electronic revolution > Nixie
ELKA (ЕЛКА) is a bulgarian company. Back in the 1960's. they started making ЕЛектронен КАлкулатор (electronic calculators). The name stayed and they produced several models, starting in 1965 by the 6521.
One of the reasons why this calculator is special, is because this is the first one to have a Square Root function !
The FRIDEN 132 was also introduced in 1965, but apparently the ELKA beat it for a couple months. The FRIDEN was using a CRT display.
This big calculator was using nixie tubes and germanium transistors.
Now, just a little bit of history: the transistor was invented some time around 1950, by 2 physicists from Bell Telephone Laboratories. Below is an extract of the patent for the transistor:
The first transistors models were using Germanium, which was later replaced by Silicon. This ELKA calculator is uing Germanium transistors.
All the calculations are done using simple transistor gates. Here is an example of one of the boards
As you can see, this is board number 25: Yes, there are 25 of these boards inside the machine. The density of the components is very low, but that may be due to the size of the tracks on theother side.