Corvus 400

Date of introduction:  1974 Display technology:  LED-modules
New price:   Display size:  8
Size:  5.0" x 3.0" x 0.9"    
Weight:  3.7 ounces Serial No:  400-110233
Batteries:  4*N cells Date of manufacture:  mth 02 year 1975
AC-Adapter:  6V DC, 750mA Origin of manufacture:  USA
Precision:  8 Integrated circuits:  Mostek MK50282A
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner

The Corvus 400 calculator uses four small N-sized batteries compared to the larger AA-sized cells of the Corvus 310 line. The result is a very small LED-type calculator similar to the Texas Instruments TI-1500.

It uses a MK50280A single-chip calculator circuit and one digit driver circuit. Learn more about Mostek Calculator Integrated Circuits.

The Corvus 400 introduced the "N"-key known from desktop calculators. It instructs the calculator to display a count of entries made in a chain. This feature is used in obtaining averages. 

Within a few month the keyboard color design was changed, don't miss the second edition of the Corvus 400. The third Corvus 400 makes use of the MK50282A calculator circuit instead the MK50280. The differences between the two chips are not yet discovered. Within some month the four unusual N-batteries were replaced with a standard 9V battery. Don't miss the Corvus 406.

The Corvus 400 was sold under the label of Radio Shack, don't miss the EC-230.

Other calculators sold under the Corvus brand are the 320, 415, 500, and 615 models. 

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If you have additions to the above article please email:

Joerg Woerner, December 29, 2017. No reprints without written permission.