The operator and controller of the low-grade Customizable calculator are simple serial operations implemented by digital logic circuits, and its random access memory has only one or two units for accumulative storage. The high-end Customizable calculator implements various complex operation programs by the microprocessor and read-only memory and has more random storage units to store input programs and data.

Customizable calculators are generally composed of calculators, controllers, memory, keyboards, monitors, power supplies, and some optional peripherals and electronic accessories, either manually or mechanically.
The keyboard is the input part of the Customizable calculator, generally using touch or sense. To reduce the size of the calculator, one key often has multiple functions. The display is the output component of the calculator, such as a light-emitting diode display or a liquid crystal display.
The integrated circuit of the Customizable calculator has a built-in automatic power-off circuit for timed non-operation. The optional peripheral devices of the calculator include micro-printers, cassette tape drives, and magnetic card machines.
Through the above introduction and analysis of the composition of the Customizable calculator, hope it helps you.