ANITA Desk Calculators using both Transistor Logic & Integrated Circuits
Power supply - AC mains.
Display is 10 digits, Nixie tubes.
4-function, %, memory, uses RPN (Reverse Polish Notation).
Mainly uses transistors, but has 5 integrated circuits made by Marconi-Elliott Microelectronics using "MOST" (Metal-Oxide Semiconductor Transistor) technology. It was claimed that each integrated circuit contains about 200 transistors.
265 x 335 x 172 mm (10.4" x 13.25" x 6.75").
Introduced 1969, circuit boards on this example date stamped mid-1970.
Made in England by Sumlock Anita Electronics Ltd, distributed by Sumlock Comptometer Ltd.
Marconi-Elliot Microelectronics was closed down in July 1971 by GEC (the British General Electric Company) during one of the
periodic industry downturns.
The whole of the British commodity semiconductor industry was to meet a similar fate.
The "Nixie"-type tube display has a separate tube for each digit. Note that the decimal point is displayed by small neon lamps.
The machine uses Reverse Polish Notation (RPN). The first number is keyed in and and the key marked "ENTER 1ST NUMBER" is pressed. The second number is then keyed in and the key for the required operator is pressed, after which the calculation is performed and the answer is displayed.
Inside the 1011, with from left to right the function boards, the memory board, the logic driver boards, and the display tubes.
Inside the 1011, with from rear to front the top function board and the memory board.
Inside the 1011, showing the 11 function boards marked eg. "Bistable", "Add/Subtract", "Divide logic", "Multiply logic".
The 3 logic driver boards, from top to bottom "Inst. Counter", "Sync. Counters", "Data Strobe".
These have the 5 integrated circuits - in metal cans mounted upside down with the leads coming out radially. There is a type MA34, a type MA37, and three type MA38, all dated here to mid-1970.
The manufacturer's and distributor's labels.
John Wolff in his Web Museum has interesting photographs of a 1011 with earlier types of circuit boards and components.
Anita Desk Calculators using both Transistor Logic & Integrated Circuits
Text & photographs copyright © 2002 - 2017 Nigel Tout, except where noted otherwise.