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This manual has been reproduced from a 1976 German publication
www.soemtron.org
We (
will take steps to remove, alter or further acknowledge this document if we are notified of any
infringements. It has been presented in good faith to aid in understanding the inner workings of the
now vintage Soemtron 22x range of electronic calculators.
It has been published by us to disseminate information about the Soemtron 22x range of electronic
desk calculators manufactured by V.E.B.
and centralise whatever information can be found about these increasingly rare early electronic
calculators.
If you have or know of any information, books, drawings, circuits, hardware, test equipment (prufgerat)
or other memorabilia relating to the Soemtron 220, 221, 222 or 224 calculators, their trade names -
Daro or Soemtron, manufactured by - V.E.B. Büromaschinenwerk Sömmerda, please email us at -
mike@soemtron.org
This document has been scanned from an original book, processed through an on-line OCR software
package to regenerate the original German text and then automatically translated to English and
imported into Microsoft Word. Layout has been duplicated in line with the original document as much
as possible to retain the flow of the original document. Drawings, circuits and photographs are scans
from the original document.
With this effort in mind some of the syntax in the document may be a little strange. Some portions
have been reworked to be more readable English text but there is obviously more to be done. If you
can help with this, or indeed have any helpful information or comments, please email us at -
mike@soemtron.org
Please use, and hopefully enjoy, this in information in the spirit in
which we undertook to generate it - as an information source for an
interesting piece of early calculator history before the advent of
modern electronics, in the days when "hands on" engineers thought
through the problems and challenges of designing equipment with
little resources, to produce the best end product they could.
www.soemtron.org
August 2019 -
Daro Soemtron 220
Elektronischer Tischrechenautomat
Bedienungsanleitung
69-220-000-5
) fully recognise the intellectual property rights of the originating source and
(*1)
mike@soemtron.org
-
Büromaschinenwerk Sömmerda, as a project to gather
Revised 21/8/2019

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Summary of Contents for Daro Soemtron 220

  • Page 1 If you have or know of any information, books, drawings, circuits, hardware, test equipment (prufgerat) or other memorabilia relating to the Soemtron 220, 221, 222 or 224 calculators, their trade names - Daro or Soemtron, manufactured by - V.E.B. Büromaschinenwerk Sömmerda, please email us at - mike@soemtron.org...
  • Page 4: Table Of Contents

    TABLE OF CONTENTS Page Introduction Keyboard (graph) Description of the structure and equipment Keyboard Display Decimal point means Processing unit Power supply Commissioning Calculations 4.1. Addition 4.2. Subtraction 4.3. Multiplication 4.4. Division 4.5. Exponentiation 4.6. Memories 4.7. Decimal points 4.8. Constant factors 4.9.
  • Page 5 12. Division with a bracket expression 13. Percentage searched 14. Numerical value wanted 15. Increased value 16. Reduced value 17. Combination Calculator (3 rule ?) 18. Interest calculation after days 19. Distribution task (3 memories) 20. Payroll with constant factor [2 memory] 21.
  • Page 6: Introduction

    The electronic desktop calculator "Soemtron 220" solves the most varied tasks at all levels of commercial and scientific knowledge technical and technical sector.
  • Page 7 KEYBOARD of electronic desktop calculator 1. Decimal point adjustment. 2. Delete key 3. Correction key 4. Decimal point key 5. Numeric Keypad 6. Sign key 7. Multiplication key 8. Addition Key 9. Result key 10. Subtraction 11. Division key 12. Exponentiation 13.
  • Page 8: Keyboard (Graph)

    DESCRIPTION OF CONSTRUCTION AND EQUIPMENT The electronic desktop calculator type 220 is a fully transistorized device. In addition to all the throat operations of the elementary calculation, he performs extensive combination calculations and exponentiation tasks quickly and mathematically exactly. The machine is built according to the modular principle, so that a secure maintenance is guaranteed.
  • Page 9: Display

    DISPLAY DEVICE The input and output values are displayed clearly legible in the display device by means of digital display tubes. DECIMAL POINT DEVICE To the left of the keyboard is a thumbwheel for setting the decimals. Before starting an arithmetic operation here is the required to set the decimal place.
  • Page 10: Commissioning

    3. COMMISSIONING The computer is designed for connection to the following mains voltages: 110V +10 % 50—60 Hz -15 % 127V +10 % 50-60 Hz -15 % 220V +10 % 50—60 Hz —15 % 242V +10 % 50—60 Hz —15 % From the factory the automaton, if no other delivery agreement exists supplied for connection to 220 V mains voltage.
  • Page 11: Calculations

    CALCULATION OPERATIONS Button 4.1. Addition Additions are possible in the calculator and in the memories. Press the (+) button to enter the addend values. The total is displayed after pressing the (=) button. The addends are entered into the calculator by In the memory I, II, III Memory recall without deletion I, II, III (▽)
  • Page 12: Exponentiation

    and the quotient is displayed. If a sum or a difference is formed before or after entering the dividend in the calculator, this sum or difference becomes the divisor when the (=) key is pressed, and with this the division is automatically executed. Example : a : b = c a :(b + c) = d...
  • Page 13: Constant Factors

    After pressing the (,) - key (Decimal point key) appears at this point the numbers 0 and 1 on top of each other to indicate the entered Decimal place. If a function key is pressed, the value automatically moves to the appropriate position.
  • Page 14: Input And Output Capacity

    5. INPUT AND OUTPUT CAPACITITY The capacity of the electronic desktop calculator "Soemtron 220" is in input and output of 15 digits. Multiplication whole: numbers The maximum positions of the multiplicand and the multiplier must not exceed 15 in total.
  • Page 15: Calculation Examples

    6. CALCULATION EXAMPLES 1. Addition Example : 512 + 309 =821 Walk through Sequence of the calculation Function key Display --------------------------------------------------------------------- 1. Decimal point position 2. Enter 3. Enter 2. Subtraction Example : 461 - 207 = 254 Walk through Sequence of the calculation Function key Display...
  • Page 16: Multiplication With Different Decimal Points

    Walk through Sequence of the calculation Function key Display --------------------------------------------------------------------- 1. Clear the memory *I, *II, *III 2. Decimal point position 3. Enter 4. Enter 5. Recall 1357 6. Enter 7. Enter 8. Recall —I 10. Recall 11. Enter +III 12.
  • Page 17: Multiplication With Different Decimal Points

    5. Multiplication with different decimal points Example : 623,3 X 1,22 X 0‚031 = 23,573 Walk through Sequence of the calculation Function key Display --------------------------------------------------------------------- 1. Decimal point position 2. Enter 623,3 623,300 3. Enter 1‚22 760,426 760,426 5. Enter 0,031 23,573 6.
  • Page 18: Exponentiation

    8. Exponentiation Example : 13^5 = 371 293 Walk through Sequence of the calculation Function key Display --------------------------------------------------------------------- 1. Decimal point position 2. Enter 2 197 28 561 371 293 9. Division Example : 225 : 5 = 45 Walk through Sequence of the calculation Function key Display...
  • Page 19: Division With Constant Divisor

    11. Division with constant divisor Example : 1266,55 : 123 = 10,297 5678,12 : 123 = 46,164 Walk through Sequence of the calculation Function key Display --------------------------------------------------------------------- 1. Clear the memory 2. Decimal point position 3. Enter 1 266,55 1 266,550 4.
  • Page 20: Numerical Value Wanted

    14. Number sought Example : 100% = 86 work pieces 62.8% = ? 86 X 62.8 --------- = 54 work pieces Walk through Sequence of the calculation Function key Display --------------------------------------------------------------------- 1. Decimal point position 2. Enter 86,0 3. Enter 62,8 5 400,8 5 400,8...
  • Page 21: Combination Calculator (3 Rule ?)

    17. Reduced value (Normal operation) Example : 16 m costs 39,00 M 19 m costs ? 39 X 19 ------- = 43,31 M Walk through Sequence of the calculation Function key Display --------------------------------------------------------------------- 1. Kommuslel1ung 2. Enter 39,00 3. Enter 741,00 741,00 5.
  • Page 22 Walk through Sequence of the calculation Function key Display --------------------------------------------------------------------- |. Clear the memory *I, *II, *Ill 2. Decimal point position 3. Enter 5640, 5 640,000 0 5 640,000 0 5. Enter 150 375,5 150 375,500 0 0,037 5 +III 0,037 5 8.
  • Page 23: Conversion Of The English Currency

    21. Conversion of English currency When converting the English currency, shillings and pence must be converted into decimal of pounds. 1 sh = 1/20 = 0.05 = 1/240 = 0.004 166 6 ... (0.0042) Example : How many Marks are: £ 25.8.11 Exchange: £...
  • Page 24: Weight Calculation

    23. Weight calculation How heavy is an oak column of 0.30 m in diameter and 3 m in height? Specific gravity of oak: 0.72 Formula: r2 X X specific weight π 0,19 X 0,19 x 3,14 X 3,00 X 0,72 = 244,845 kg Walk through Sequence of the calculation Function key...
  • Page 25: Calculation Of The Cutting Speed

    (6 X 5) (3 X 4) Example : (-----) - (-----) = 11 Walk through Sequence of the calculation Function key Display --------------------------------------------------------------------- 1. Clear the memory 2. Decimal point position 3. Enter 4. Enter 6. Enter 8. Enter 9. Enter 11.
  • Page 26: Amortization Schedule

    Sequence of the calculation Function key Display --------------------------------------------------------------------- 3. Enter 150, 150,00 4. Enter 3,14 3,14 471,00 471,00 7. Enter 300, 141 300,00 141 300,00 141 300,00 10. Enter 1 000, 141,30 11. Recall 141 300,00 ▽II 141 300,00 13. Enter 1 50, 942,00 942,00...
  • Page 27: Invoice Control With 3 Save

    During these amortization calculations only multiplications with the same folder are performed. The respective capital is multiplied by the factor 4.25 (semi-annual interest rate). The result is the interest, which is subtracted from the annuity. Your calculated repayment is subtracted from the capital so that the residual capital results.
  • Page 28 27. Invoice control with 3 memories ------------------------------------------------------------------------- Invoice Execution ------------------------------------ Expiration date| Invoice total Page | Number | Number | Sheet | ------------------------------------------------------------------------- 30. 8. 1965 577 209,90 ------------------------------------------------------------------------- Discount for cash until expiry date ---------------------------------------------------- Nett amount | Factor Good value Date of issue -------------------------------------------------------------------------...
  • Page 29: Series Development [Minus Division]

    Sequence of the calculation Function key Display --------------------------------------------------------------------- 180 228,92 7. Enter 0.06 10 813,74 —I 10 813,74 9. Recall 169 415,18 169 415,18 11. Enter 3,25 3,25 12. Enter 32 419, 105 361,75 105 361,75 105 361‚75 15. Enter 0.04 4 214,47 —I...
  • Page 30: Labour Statistics

    Walk through Sequence of the calculation Function key Display --------------------------------------------------------------------- 1. Clear the memory *I, *II 2. Decimal point position 3. Enter 1,000 000 1,000 000 5. : 1,000 000 6. Enter 0,333 333 —1 8. Recall 1,000 000 ▽II 1,000 000 10.
  • Page 31 ∑ Z1 1 100 Zu 1.: ---- ----- 122% ∑ Z2 ∑ L1 X Z1 (330 X 200) + (380 X 400) + (440 X 500) Zu 2 : --------- --------------------------------------- ∑ L0 X z) (300 X 200) + (330 X 300) + (370 X 400) 438 000 ------- 143%...
  • Page 32: Square Root Calculation After The Iteration

    Sequence of the calculation Function key Display --------------------------------------------------------------------- 31. Recall 307 000,00 307 000,00 33. Enter 900. 341,11 341,11 35. Recall 390,18 398,18 37. Recall 341,11 1,17 The calculated numbers have to be multiplied by 100, since they are percentages. 30.
  • Page 33 1 (630,01 - (------ + 23) = 25,195 870 1st Approximation 630,01 - (---------- + 25,195 870) = 25,100 183 2nd Approximation 2 (25,195 870 630,01 - (---------- + 25,100 183) = 25,100 000 3rd Approximation 2 (25,100 183 Sample: 25,100 000 2 = 630,01 Walk through Sequence of the calculation Function key...
  • Page 34: Cubic Root Calculation After The Iteration

    31. Cubic root calculation without the iteration formula Formula: Yn + 1 = Yn + --- ( --- - Yn ) As with the 0uadrat root, it is necessary to have a first Initial approximation is estimated. For this purpose, the Radicandin front of the comma from left to the left in groups of three digits ...
  • Page 35 Sequence of the calculation Function key Display --------------------------------------------------------------------- 279,430 000 6,614 911 6,614 911 6,500 000 ▽I — 6,500 000 0,114 911 0,114 911 16. Enter 0,030 104 0,038 304 18. Recall 6,538 304 ▽I 6,538 304 42,749 419 42,749 419 22.
  • Page 36: Appendix: Technical Data

    Technical Datasheet ETR Soemtron 220 The ETR "Soemtron 220" is a fully transistorized four-function calculator with ferrite core memory, input keyboard and digitizer tubes for the value display. 1. Size : Width: 380 mm Length: 464 mm Height: 194 mm 2.
  • Page 37 Exponentiation Memory function with retransmission and selective deletion Constant factor Automatic Decimal point (fixed point) Signed calculation Balance Rounding up the last digit Control in case of capacity overrun 12. Operating conditions: Temperature range of +15°C - +35°C maximum relative humidity 80% Safety instructions for the operator Due to its fault-free covering, the computer has no endangerment for the operator.

This manual is also suitable for:

Soemtron 221Soemtron 222Soemtron 224

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