Texas Instruments TI-2550

Description

Brand: Texas Instruments
Model: TI-2550
Type: Calculator
Picture: TI-2550
Batteries: AA x 4 or AA NiCad x 3
Lifetime: Introduced: 1974
Terminated: 1976
Notes: The Texas Instruments TI-2550 is their third model after the TI-2500.

TI-2550 battery compartment It is a big and heavy 8 digit calculator with a LED display, memory and percentages.

It runs either on four non-rechargeable AA batteries, or on three rechargeable NiCad batteries, leaving one slot empty. If using a power adapter, there are two versions, see illustration.

Use the "F 2 3" slider to switch between floating point, or rounded currency modes with a mantissa of two or three decimals.

A non-zero value in memory is indicated by lighting up the top left and top segments of the leftmost digit. The effect of this is that a small "c" is visible top-left when there is a non zero value in memory and a negative number is displayed.

Funny enough, erros are indicated by lighting up the bottom left and bottom segments. So when a "E" is displayed, the calculator has an error condition with a negative number displayed and a non-zero value in memory. :-)

The last operation is repeated when the "="-key is pressed.

There is a page on this model on the site of The National Museum of American History, see it here (link validated 2024-07-16).

Peripherals

A power adapter. Use power adapter AC9120 when 4 non-rechargeable batteries are installed. Use power adapter AC9130 when using 3 NiCad batteries.