Denon DEC-521 Desktop Calculator
DEC-521 Image Courtesy Rick Furr (left)
Columbia COLCA 52 Image Courtesy Takaharu Yoshida (right)
Sincere thanks to both of these gentlemen for providing these images.
Hybrid IC/Transistor Desktop Electronic Calculator.
12-digit Nixie display, four function, fixed decimal with
accumulating memory register and constant. Introduced
in May of 1970. Also marketed as the Columbia COLCA 52 in some countries.
See the Old Calculator Web Museum exhibit on the
Denon 61A4 for an example of
Denon's first desktop electronic calculator.