The following calculators have been owned and used by Hans Sundgren.

HP 17B with infrared printer

Technical data

- 22x2 digits, LCD
- 37 keys
- 6 kB RAM
- 148 x 80 x 15 mm, 120 g
- Power consumption: ??? mA
- 3x1.5 V xxx cells
- No external power
- Printer connection via IR

Documents

None

**Xxx 1990 **

Hans gets this calculator as part of a work compensation program. He selects the calculator himself and wants an economical type of calculator with possibility to program any problem. This calculator has also an IR-connected printer.

Good

- Very inutitive, easy to program
- Robust design

Bad

- The printer has a high power consumtion
- ???

End of life 19xx

In XXX 199x the calculator is stolen when is is stored in a breifcase in the car parked in Djurgården, Stockholm. The printer is left in Västerås.

Commodore SR4148R

Technical data

- 10 digits, 7-segment, red LED
- 48 keys
- 2 storage registers
- 151 x 79 x 36 mm, 158 g
- Power consumption: 400 mA
- 3xAA NiCd accumulators
- 6 V DC external adapter

Documents

None

**August 1977 **

When entering the final 4'th year of his engineering studies, calculators were now accepted. So Hans buys a scientific calculator with R/P functions needed for his last years study of high voltage electrical engineering.

Good

- All possible functions included
- R/P included, which was not the case with other calculators.

Bad

- High power consumtion, required AC voltage after some time.
- Buttons without "click".

**Xxx 197x**

Hans read the magazine "Radio och Television" and sees an ad describing the Sinclair Cambridge calculator from Great Britain.

Good

- A special K-key simplifies constant calculations.
- Small, quite inexpensive.

Bad

- Not 100% correct calculations. A correct result of 2.0 could be presented as 1.9999999.
- ???

**Xxx 197x**

Calculators are not accepted when Hans starts the secondary school, studying to be an engineer. So Hans is forced to learn how to use a slide ruler.

Good

- Requires no batteries or power supply.
- Gives the user a good mathematical understanding.

Bad

- The result is givien in only a few decimals and the number of zeros has to be manually "calculated".
- Not suitable for addition and subtraction, even though it is theoretical possible.