CONTEX - 30

TECHNICAL DATA of the Electro-Mechanical Calculator CONTEX-30 ********************************************************************** Serial Number: 473169919 Dimensions: (ca.) Width = 8 " / 20 cm Depth = 10 " / 25.5 cm Height = 4_1/4" / 11 cm Weight: (ca.) 7_3/4 lbs / 3.5 kg Power Supply: 220 V AC / 45 W Mechanics: 10-Block-Keyboard, Serial-to-parallel Conversion Rocking Segment Mechanism Functions: Add, Subtract, Multiply, Divide Registers: Input = 10 Decimals Counter = 1 Decimal ( RED FIGURES ONLY !!! ) Arithmetic = 11 Decimals |

OPERATING CONTROLS 1 Keyboard 5 Subtraction 9 Tabulator 2 Clear 6 Position Marker 10 Addition 3 Multiplication & Correction 11 Control Display 4 Division 7 Decimal Marker 12 Result Display 8 Return Key START: ------ Press [C] key (2) to clear arithmetic & counter units. Shift the red slider (6) to the right to clear the input unit. ENTER A NUMBER: --------------- The actual number of digits entered are shown with the red slider (6). If wrong digits are entered, push the slider to the right to clear input. ( IGNORE THE RED FIGURE IN THE COUNTER !!! RELEVANT FOR DIVISION ONLY ) ADDITION: --------- Everytime a number is entered and the [+] key (10) is pressed, the motor starts and the number will be added to the content of the arithmetic unit. After the procedure the keyboard will be cleared. THE INPUT IS "BLIND" !!! SUBTRACTION: ------------ Enter the number and press [-] key (5) to start the motorized procedure. NEGATIVE RESULTS are displayed in the arithmetic unit as the COMPLEMENT of the next higher 10, 100, 1000, ... Example: -12 = 99...9988 MULTIPLICATION: --------------- Example: 123 x 45 = 5535 Press [C] key to clear arithmetic & counter units. Shift the red slider to the right ... Enter the multiplicand (=123). Press the [X] key. The multiplicator (=45) has two digits. Press the key of the "1"-Position =[5] key, to add the multiplicand (=5) times. The arithmetic unit shows the intermediate result (=615) and the input unit is now shifted to the "10"-Position. Press the key of the "10"-Position =[4] key, to add the multiplicand (=4) times. The result (=5535) is in the arithmetic unit. Shift the red slider to the right to clear [X] and input unit. MULTIPLE MULTIPLICATIONS WITH A CONSTANT: ----------------------------------------- Example: 123 x 45 = 5535 123 x 67 = 8241 123 x 89 = 10947 Enter the constant (=123). Press the [X] key. Push the GREY KEY (="RE-STOP") close to the RED POSITION MARKER. Enter the 1st factor ( =45 in the way 5-4 ). This starts the motorized multiplication. Clear [C] the result (=5535). Shift the RED POSITION MARKER to the GREY KEY and enter next factor ( =67 in the way 7-6 ). Clear [C] the result (=8241). Shift the RED POSITION MARKER to the GREY KEY and enter next factor ( =89 in the way 9-8 ). Clear [C] result (=10947). Shift GREY KEY & RED POSITION MARKER to the right to clear [X] & input. DIVISION: --------- Example: 22 : 7 = 3.14285714 Remainder 2 Press [C] key to clear arithmetic & counter units. Shift the red slider to the right ... Enter the dividend (=22). Press the tabulator [ <-:- ] key to shift it in its left position. Press the [+] key to transfer the input into arithmetic unit. Enter the divisor (=07). Press the tabulator [ <-:- ] key to shift it in its left position. Press the [DIV] key. Press the [-] key to start the motorized subtraction of the divisor. When the motor stops, the RED FIGURE of the counter unit shows the 1st digit (=3) of the result. Pressing the [ -> ] key, the NEXT DIGIT will be calculated and shown as the RED FIGURE. Continue pressing [ -> ] key until the maximal number of digits are calculated. The remainder (=2) is shown in the right window of the arithmetic unit. Shift the red slider right to clear [DIV] key and input unit. REMARK: PRESS THE [C] KEY, IF THE DIVISION PROCEDURE DOESN'T STOP R E M A R K S : ======================================================================= Two lines of interesting and innovative mechanical calculators came on the market under the name » CONTEX « in the '50s and '60s : The first was a key-driven adding machine in style of a Comptometer, with a "half" keyboard and simplified mechanism: CONTEX-A & CONTEX-B. The second was a series of 10-Block-Keyboard machines. The CONTEX-10 is a manual one. The CONTEX-20 is motor-driven. This CONTEX-30 has improved motor-driven multiplication and division. The CONTEX-55 has its own DIVISION REGISTER to complete the division full automatically. impressum: *********************************************************************** © C.HAMANN http://public.beuth-hochschule.de/~hamann 03/23/08 |