Desk calculators with electron tubes
The development of electronic calculators since the 1950s is at least as interesting as the
development of broadcast engineering in the 1920/30s.
The first electronic desk calculator in the world (1962) is a real milestone. The
modern-looking monster features 144 electron tubes and belongs consequently to the first
generation of calculators. It has a wonderful glowing display. However, the
tube based computer can only compute with the four basic arithmetic operations and
costed the price of a VW beetle and an holiday trip.
Anita Mark C/VIII (Manufactor: BELL PUNCH Co, England), an historic calculator that revolutionised calculating on desktops. For the first time, you could multiply and divide without mechanics and noise. Technically speaken, the device was actually obsolete in 1962. The calculator works in decimal system, just as every other mechanical sprocket wheel machine. It still took two years until transistorized desk calculators (IME 84) came onto the market.
The "nightly" Anita inner life: The thyratrons flow redly, flashing during calculating.
This is a part from the numeric display. The gas-filled nixie tubes (glow lamp's principe) came onto the marktet just in time.
The upper circuit board contains a ring counter. The gas-filled thyratrons are very small. This was the only way to place approx. 177 pices into a manageable case. These relay tubes have only two states like mechanical relays. Additionally there are 11 vacuum tubes (ECC 81, left side) built into the calculator.
The complete counting decade with a nixie tube is shown below.