Before revision: History Timex CA3A0441 calculator watch Calculator watches first appeared in the mid 1970s introduced by Pulsar (1975, then a brand of the Hamilton Watch Company)"Going Digital", Time, December 22, 1975"History of LEDs - Chapter 1" at Rensselaer Polytechnic Institute website.
After revision: History Calculator watches first appeared in the mid 1970s introduced by Pulsar (1975, then a brand of the Hamilton Watch Company)"Going Digital", Time, December 22, 1975"History of LEDs - Chapter 1" at Rensselaer Polytechnic Institute website.