Seltener LCD Calculator der amerikanischen Firma National Semiconductor, 1977, Cal. CW-01. Zahlreiche mathematische Rechenfunktionen, Licht.
NSC LCD calculator, Cal CW 01
The scientific calculator and watch module is claimed to be the first to use liquid crystal display technology. In addition to presenting a six digit continuous display of hours-minutes-seconds, the unit also has a month/date calendar, AM indicator and dual night viewing lights. In the calculator mode, it employs algebraic logic, has full scientific notation, trig and log functions, store and recall memory, pi, powers of numbers, register exchange and reciprocals.
Hybrid construction is used to mount the chips on a small p.c.b., on which is also mounted a miniature 5 x 4 matrix keyboard and field effect LCD with 1/8 inch high digits.
Thirty-six possible switch functions are available on the dual function keyboard. Normally in the numeric entry mode, a function key calls up the upper case functions such as natural logs and sine or cosine. Another key is pushed to place the watch madule in the timekeeping mode. The six most significant digits are displayed for calculations, with switches on the side to call up the next six significant digits, as well as the calendar/date functions. Switching to the calendar mode from the timekeeping mode is done by pushing any digit key.
Unlike conventional digital watches, there is no complicated procedure for setting time or date, since the calculator keyboard may be used instead. For example, the user can add or subtract seconds by merely pushing the plus or minus key and then the desired number of seconds. Similar procedures can be followed to set hours, minutes and days.
Also, unlike the standard digital watch, the watch-calculator module can be used to store numeric information unrelated to either calculations or time-keeping. For example, if a user wants to remember a telephone number or pricing on an item and has no paper, the number can be punched on the keyboard and entered into the calculator memory. There it will remain as long as there are live batteries in the module, or until the user calls it up and erases the informaion.