Inside a calculator

@nenuadwani-pb4lOD • Oct 27, 2024

Oct 27, 2024

1.6K

HELLO,
I am an electronics and communication engineer persuing third year.I opened a calculator and was amused to find that it contains only a lcd, a chip and a ciruit layout that helps in the input through the keypad.Now my mind is boggling as to what is there in that chip that makes a calculator work.There may be some programming about which I am sure. But I want a detailed information as to how all this happens. Can some one help me please.

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Saandeep Sreerambatla

@saandeep-sreerambatla-hWHU1M • Sep 14, 2010

In general words , Calculator works on the calculations using logic gates.
It involves CMOS (Complementary metal-oxide-semiconductor) Technology for the circuit.
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nenuadwani

@nenuadwani-pb4lOD • Sep 15, 2010

Ya I am aware of that. I have found out that a small IC is attched to the chip which stores the programming. But the model i opened had the circuit made on a polythene like structure and the circuit was painted with black similar to a layout on a PCB. I still want to know the detailed working.
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Saandeep Sreerambatla

@saandeep-sreerambatla-hWHU1M • Sep 16, 2010

you can design a basic calculator using logical gates rite?
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nenuadwani

@nenuadwani-pb4lOD • Sep 17, 2010

thats right. But what about the plastic material on which the circuit is drawn. How signals move through that?
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aj_onduty

@aj-onduty-BvuwMK • Sep 17, 2010

nenuadwani
thats right. But what about the plastic material on which the circuit is drawn. How signals move through that?
Are you talking about the printed circuit board?
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shreyasm89

@shreyasm89-jGobVm • Sep 17, 2010

@aj-No buddy...he is already aware of a PCB.In fact he expected to find a PCB inside but instead found a black polythylene-like material.
@nenu-The small chip that you are mentioning is the microcontroller IC. Was that black material between the numeric keypad & the chip?
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patsham

@patsham-AsXMka • Sep 17, 2010

you can show us the picture of that circuit so that we can help you.
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nenuadwani

@nenuadwani-pb4lOD • Sep 18, 2010

shreyasm- you are ryt. I expected a pcb, infact i got a pcb based circuit also in other calculators. but the model i opened first didnt had a pcb. the whole circuit was on polythene just lyk it would have been on a pcb.
i will try providing a picture of that circuit. no the ic is on the chip itself.
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Van Helsing

@van-helsing-nwELoN • Sep 21, 2010

I was aware that a PLC (programmable logic controller) was a computer inside application, not vice versa. 😕

The "all plastic" inside with embedded IC's under polimeric black glue drops is the china-way of making things cheaper. A PCB is made of polymer/glass fiber board with copper wiring layers. The plastic PCB (Poly Carbonate) or other, with carbon wiring layer is a cheaper more flexible way of making PCB's. And thinner too. The cost of a microprocessor or a digital integrated circuit is mainly connections and body. For very large production scale is cheaper to mount IC's directly on the PCB alas protected by a glue drop.
Obviusly, under the drop you'll find gold wires connections to carbo-something circuit threads to an fro keyboards and LCD display, and a chip wich holds a microprocessor usually 4 bit wide, a RAM a ROM and an I/O logic as usual in a microcomputer. The ROM holds the software for making the calculator ... calculating. 😒
Cheers...
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nenuadwani

@nenuadwani-pb4lOD • Sep 22, 2010

I am thankful to all for clearing my doubts. Now I am clear about what I actually saw inside that calculator.
Thanks a lot crazy engineers.
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ITPROFESSIONAL

@itprofessional-7OFia1 • Apr 6, 2023

these all are PLC's
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