Compex - SR-55

Description

Brand: Compex
Model: SR-55
Type: Scientific calculator
Picture: Compex SR-55
Batteries: AA x 3
Lifetime: Introduced: 1976
Terminated: unknown
Notes: The Compex SR-55 is a plain scientific calculator. Judging from the look of this calculator, and also it's model designation, this is probably a Commodore calculator rebranded by Compex.

I have also found a Compex SR-40, but the one I found is broken and I haven't therefore added it to my calculator collection. The circuit board of the SR-40 is identical to the circuit board of the SR-55. The difference is that the SR-40 lacks all scientific functions from the keyboard.

The "y^x"-key performs the decimal log of a number.

The fluorescent display is oriented left-to-right, meaning that when you type a number the first digit shows up on the left side of the display, and following digits are appended at the right.

This calculator has some nice display features as well:

Spacer Memory display When the calculator's memory stores a non-zero value, the bottom-right segment of the leftmost digit of the calculator's display lights up, as shown on the example on the right.

Spacer Parenthesis display And when the calculator's has a pending parenthesis (out of a maximum of 2 pending parenthesis operations), the top-left segment of the leftmost digit of the calculator's display lights up, as shown on the example on the right.

Peripherals

A power adapter.

©2023 Ernst Mulder