1977 · Slim Liquid Crystal Calculator · Work 951 of 1,871
A white work table in a product design studio in Kronberg in the Taunus hills, a hand in a grey wool sleeve drawing a flat pocket calculator out of a close-fitting black plastic sleeve, a slim matt black rectangle eight by thirteen centimetres and half a centimetre thick with rounded corners, at its top a recessed plain pale grey display window, below it twenty-five small round domed keys in a grid of five by five in black, dark brown and green, one key bright yellow, every key plain, smooth and unmarked, sheets of tracing paper and small white foam models beside it, wooded hills through a wide window, soft daylight from the left.
What it was used for
The ET 33 of 1977 belonged to Braun AG's control series, designed by Dieter Rams and Dietrich Lubs, with Ludwig Littmann named as a contributor. It showed 8 digits on a liquid crystal display with black figures on a silver ground, legible even in bright light, and was 5.4 mm thick. It sold for 76 DM with a 2-year guarantee. The series ran from the ET 11 of 1975 to the ET 100 of 2002, from the ET 22 on and except for the ST 1 with convex keys, spaced key pitch and a colour-coded keypad.
What was new
What marked the ET 33 was its height and where that came from. Its predecessor, the ET 22 of 1976, had a green fluorescent display and ran on 2 AA cells of 1.5 V each or on a mains unit. In the ET 33 a liquid crystal display and silver-oxide button cells took their place; the button cells made 5.4 mm possible; the label "slim" referred to exactly this. The advance lay not in the arithmetic unit but in display and power source. The barb: what made the calculator thin also tied it to cells that could not be recharged - and the outward form outlived the electronics by decades, into the 2000s.
What the sources leave open: Thickness, price, display and cells come from the compilation "Die Taschenrechner von Braun. Das gesamte Programm von 1975 bis 2004", not from a Braun archive. The same compilation gives 76 DM for the ET 22 of 1976 as well; this could not be cross-checked. No museum object page for the ET 33 was found, only for the ET 55 of 1980.