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TI-55: Difference between revisions
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Internal design
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[[Category:Pocket calculator]] | [[Category:Pocket calculator]] | ||
[[Category:Bubble LED]] | [[Category:Bubble LED]] | ||
{{Infobox calculator|name=TI-55|introduced=1977|prog_lang=Keystroke|supply=9V (stepped up from 2.4V supplied by internal battery pack | {{Infobox calculator|name=TI-55|introduced=1977|prog_lang=Keystroke|supply=9V (stepped up from 2.4V supplied by internal battery pack), 5.7-8.6V external AC power supply|dimensions=145(l) x 80(w) x 45(h)mm|ports=DC power connector (on BP7 battery pack)|display_type=[[Bubble LED]]|power=120mW in power on state, 80mW in standby}} | ||
The '''TI-55''' was an early programmable scientific calculator released by [[Texas Instruments]] in 1977. | The '''TI-55''' was an early programmable scientific calculator released by [[Texas Instruments]] in 1977. | ||
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== Internal design == | == Internal design == | ||
At the heart of the calculator is the Texas Instruments TMC1503NL calculator ASIC, which is the only integrated circuit in the calculator. Similar to other models in the Texas Instruments SR series, a metal dome based keypad is used, which provides noticeable tactile feedback when keys are pressed. As with many other pocket calculators of the era, the display uses bubble LED technology. The display has a 8 digit mantissa and two digits for exponents. | |||
Battery power is provided by the Texas Instruments BP7 rechargeable battery pack. The BP7 contains two AA nickel-cadmium rechargeable cells, along with a board containing the the internal and external power connectors along with a DC-DC converter to boost the 2.4V output of the cells to 9V for use by the calculator. The external power connector accepts power supplies ranging from 5.7V to 8.6V AC. The internal power connector has two wires, red for negative and black for positive, inverted from the standard wiring colours. | |||
== External resources == | == External resources == | ||