M. Pham

( Adopted by Dan Leimer )


What is the fundamental purpose of the device?
Calculators are tools that can help you basically solve different types of problems that relates to mathematics. It speeds up the progress and makes problem solving easier. They are pretty much used by many people ranging from middle school students to busy adults in the business world.


What energy transformations are seen in its operation?
Modern Calculators are powered with electricity. Either batteries or solar cells are used to power a calculator. The solar cells power a calculator by converting sunlight into electricity. These are mainly found in the more simpler calculators while the graphing and some scientific calculators manage on the energy batteries provide.


What sensors/controls are designed into the device?
Calculators has a bunch of buttons/keys that represents a specific function or number. When the key is pressed down, the corresponding function will either appear on the screen or will open new functions. (ex. the graphing calc.)


What material(s) are essential to the device?
  • Processor chip
  • Keyboard sensors
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  • Keyboard membrane
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  • Batteries/solar cells
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  • Keys
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What is scientific principle is central to its operation?
  • How can a calculator know which button you are pressing?
  • How does a calculator know when and how to show and not show a certain symbol in the screen?
  • How does this all work!??!?!!??!

Calculators work by using electric currents. In calculators, there will be inputs [the keys] that go through a series of gates to end up with an output[numbers/functions on screen]. The "gates" are mini electric switches called transistors. Transistors basically allow current to either flow through it or not depending on the inputs. Transistors are either on or off. When these switches are on, current will flow through, but when they are off the current will not be able to get through.

When a key is pushed down, it makes contact with they keyboard membrane, which is the rubber material under it, the membrane then makes contact with the electrical sensor creating a current. The current with turn on the corresponding transistors and reach the processor chip. Each key will have diverse pathways to reach the processor chip so the transistors they meet will be different than another key.

To know more about Transistors I would suggest this page!

The processor chip will figure out what number for function that was pressed and show it on the screen. This will continue to happen when you pressed more keys until an operation key is pressed ( -,+, x, =, etc...).The numbers will be stored in a register which is pretty much the calculator's memory. And when the key = is pressed, the calculator will automatically finish the equation and show you the answer!


What does a typical device look like?
Four-Function Calculator : Scientific Calculator : Graphing Calculator


What changes have there been (or could there be) in this device?
Before there were devices that can solve the problems themselves, our mind was the calculator. There were also the hand-made abacuses which uses beads or any other counting materials in order to do mathematics. Then soon after that the very simple Four-Function Calculator was invented. This calculator will do the basic mathematics and as more and more functions are created, the calculator became much more complex resulting in the Scientific Calculator and the Graphing Calculator.

Related Devices


What other devices serve a similar purpose?
Cell phone
Computer Calculators


What other devices work in conjunction with this device?
Cell phone Calculators
Computer Calculators


What other devices use the same scientific principle?
Computer Keyboard
IPod (Nano) (Chromatic) (Mini)
Wii Remote
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