Questions tagged [calculator]
The calculator tag has no usage guidance.
59 questions
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Calculator made from scratch [closed]
See, I know it might be a dumb question, but I would like an answer, however dumb it might be.
I never did any electronics before. However, I had an idea in mind that even if I can't do it right now I ...
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How to prevent calculator LCD zebra strip from failing
Calculator after some time gets problems on the LCD, some digits are not showing. That's due to loose (failing) zebra connectors.
Why do they fail, if they are melted in place? What can I do to ...
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What is wrong with this circuit? It's supposed to divide the two input DC voltages but its showing an erratic waveform as its output
Based on the following schematic, where V+ and V- are +15 and -15 V respectively:
Its transfer function is supposed to be: $$V_{out} = \frac{V_1}{V_2V_R}$$
I made the following circuit in LTSpice:
...
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Do scientific calculators (non-graphing calculators) have a free running clock?
I am taking a course on IoT devices and I was wondering how generic calculators achieve long battery life given they operate with no more than a couple of coin cells at best. In case they have a free ...
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What are the names of screens used in "Basic calculators"?
I was trying to power a basic calculator that day with a power source and I started from 0V going up to 1.5 v I noticed the calculator screen turning out to show a "0", but I could not do ...
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Identify this 1980 vintage Canon calculator "all-in-one" IC
I am attempting to reverse-engineer a Canon "P10-D II" desktop calculator (assembled circa 1980).
The main PCB is single-layer which makes life easier apart from the fact that I cannot find ...
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Need help shrinking a 4-bit binary Adder/Subtractor/Multiplier calculator circuit
Project Description: A mini-calculator that performs addition, subtraction, and multiplication on two 4-bit inputs (0-9) and displays the inputs and resulting numbers in 7 segment displays. Aside from ...
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Making a simple calculator with ATMEGA32
I try to create a calculator with ATMEGA32 but it did not work correctly! For example it do operations like this (2/1=0),(5*6=12808),(22+88=12746). I know that something is wrong but I cannot find it ...
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How do random number generators in calculators work? [closed]
I have a TI-30xIIs scientific calculator. I was playing around with some of the functions, and I discovered it had a random number generator. I became curious as to how it worked. My first thought was ...
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HOMEWORK: Need assistance inputing Mesh Analysis complex equations into TI89
I am having calculator difficulties in regards to inputting my mesh equations into my TI-89. The answer I am receiving is not the answer that was presented in the solution provided by my TA. I also ...
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Calculator Algorithmic Error (Bowmar MX140 [1974])
My senior colleague recently retired and left behind a Bowmar MX140 calculator that I've managed to repair
After playing around with it I've noticed it has some error with certain functions.
As an ...
user103993
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How to decide which key was pressed on a calculator?
Hi all,
I'm trying have an arduino read key presses on my calculator. The calculator does it by pressing the keyboard membrane to the PCB and connecting two points, so each key has two of these ...
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Is it possible to read calculator LCD values?
Hi all,
I'm thinking about a project, but I have no idea if it's even possible...
So the general idea would be to have a calculator that can display letters and other characters. I have a very basic ...
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Help needed with resistor value for charging NiMH batteries
I have an old calculator which contains 4 2/3 AA NiCd batteries in series. These batteries are very old and need replacing, so I'm going to replace them with 4 2/3 AA NiMH batteries in series, which ...
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How to calculate voltage-power to lower voltage-power?
I have a solar panel 18V 2W. How do I calculate how much power that is at 5V?
Thank you in advance
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Bulding a physical calculator from scratch [duplicate]
As you can probably tell I am relatively new to the electronics scene and I'm rather stuck on a project I'm doing for school.
I am on my second year of an Electrical engineering degree, tasked to do ...
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How to calculate how much wight a motor can lift? [duplicate]
I know it might be a naive question but am not really an electrical or a mechanical engineer, but am in a situation here and I need some help.
I work in motorized rolling doors and I need to know how ...
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How to build with logic gates?
I'm thinking of ideas for a school project and one of the better ones was to build a calculator from scratch using only wire and basic electrical components. I've seen very many marble, Lego, domino, ...
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How can I convert binary into multiple 7 segment displays [closed]
I've been trying to make a decimal calculator using binary adders that feed into 3 x 7 segment displays. I cant find an efficient way to do this. If someone could point me to the correct resources, or ...
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Yagi Calculator vs. Bruteforced values?
I started trying to build my own Yagi. So i ran into maybe some very well known Websites that show how to do it - however, i wanted to try with some theory first, before actually attempting to build ...
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How to 'Shift in Parallel' in a shift register?
I am trying to design a basic calculator that can add, sub, mul and div with Logisim. To store the operands I am going to use shift registers. I have recently learned about them and I understand what ...
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How to convert fixed point binary numbers to BCD? [duplicate]
I am trying to make a calculator that can do fixed point calculations but I don't know how to display them in decimal (BCD). People have told me to use reverse double dabble but I am looking for ...
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Design of supply for nichrome wire heater
I have two Cr20Ni80 nichrome wires having 1m length each, 24 SWG and a resistance of 4.390 Ohm/m. I need to heat up a furnace to 450 degree Celsius. How can I calculate the supply voltage and current ...
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current limiting filament bulb, revisited
I'm trying to size a bulb to limit DC booster pack current (harbor freight viking lithium) from overloading the 12V aux port (cigarette lighter) wiring which is fused at 15A. I'm ideally looking to ...
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3.6V Circuit and 2.8V LED
I'm trying to figure out a good LED + resitor pairing for my circuit. However, I'm provided with a challenge and limited knowledge.
Here's the situation:
I'm creating a minimized version of THIS ...
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What is the Chip-on-board ic used in calculator, how to obtain one and how to use it?
In any calculator there is a black dot blob such as this :
After searching on what it is, I find that it is a Chip-on-board controller but i can't find what is the type of or how to buy or how to ...
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How to direct input and output of circuit for multifunctional 4 bit calculator [closed]
I am trying to build a 4 bit calculator that can add subtract and multiply using a FPGA board (Altera DE2). I have an adder/subtractor and multiplier already built and functioning but need to know ...
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Saving to cassette with 80s BASIC calculator, TI-74
This 80s calculator, a TI 74 has a function that lets you save BASIC programs to a cassette tape. But, I don't have the cable to connect to a tape deck (or MP3 recorder?) So, I put my oscilloscope on ...
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How calculator's processor works in a base manner? [closed]
For example, when we click the "3" number button or "+" button, what it sends to processor ? I want an answer something like = " It come first MAR, then goes to Memory, then comes ALU " in this manner ...
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Powering a calculator's liquid crystal display (LCD)
Hello, so I'm trying to use a calculator's LCD for a project of mine and I want to put a current through it. However, the LCD is powered by the "sheet of plastic" shown in the picture, circled in red. ...
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Would this circuit work as a binary calculator?
Forgive me if this is a stupid question with a poorly drawn circuit diagram. I've never really made anything electrical before, so this is all very new to me.
I've recently been wondering how ...
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Calculating capacitance on breadboard vs PCB tracks
Is there an equation I can use to calculate:
the actual capacitance between two PCB tracks close together and
the actual capacitance between two adjacent holes of a breadboard
I believe such ...
user116345
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How to build a division logic circuit? [closed]
I understand division in binary but applying it in a circuit is confusing. so far i have built adders/subtraction and multiplication circuits. i think i should have extra bits for radix bits. simple ...
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LEDs inside of solar-powered calculators
Why do a lot of solar-powered calculators contain red or infrared LEDs that are hidden from the user? So far I have only seen this in Texas Instruments calculators.
Here are some examples of this in ...
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"High Voltage" Logic levels why they are rare
I'm continuing to dissect and learn from this old (1974) calculator. One thing that surprised my was that the pins of the main IC have both negative and positive voltages 0 to ±28V. Having worked ...
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Studying the PCB of a 70s calculator. What were they thinking?
I've been studying the PCB from an ELSI 8002 calculator from 1974. I'm thinking of repurposing the case for a project, though now that I've fixed it (by re soldering the battery connectors) I don't ...
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How to claculate LM-723 regulator circuit headroom above the intended output voltage
I need to calculate the transformer VA for bipolar regulator circuit using LM723 so I need the voltage drop or may be a headroom for LM723 under load. The data sheet is silent about it. Is there ...
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Calculator with MSP430 in Assembly Language
I am programming a calculator in assembly language with the MSP430g2553. I have a 4x4 membrane keypad and an 2x16 LCD. I already can display numbers in the LCD with the keypad. The issue is that the ...
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Antenna feed line calculator
I'm working on designing a board with the RFM22B-S2 SMD Wireless Transceiver - 915MHz. The board module requires a 50 ohm feed line to the antenna. I've been looking at trace impedance calculators and ...
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What type of processor in usual 8-digits pocket calculator?
There are a lot of +,-,*,/,CE,MC,M+,M-,MR buttons 8-digits calculators on market with keyboard layout like:
...
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Problem in a boost calculator circuit
In order to get an output of 100V-300v (for the ultrasound piezo drive ) from a 3.3V output of the microcontroller.
I have built the boost circuit according to this circuit:
But there is one point ...
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Breadboard computer [closed]
Is it possible to make a simple computer entirely with breadboards and basic electronic components? Is it feasible to, for example construct a scientific calculator in this way?
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Where did these Ohms come from?
I am new to electronics and am tyring to figure out something that is a bit disturbing to me. I am trying to figure out the amount of resistance I need to put in series before an LED, and the equation ...
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PCB Crosstalk calculators... Center line distance or trace separation
I am still a beginner in this field, and recently I've learned about Crosstalk and Crosstalk calculators. I've tried the one on EEweb, Saturn, Ultracad and some others. Some of these calculators ask ...
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How to make a Calculator? [closed]
I am new to electronics programming. I am currently using C#.
Can you please tell me how to programme a Calculator, what programming language should I use? Can I use C/C++?
And what components ...
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Why do TI (Texas Instruments) graphing calculators not use TI chips? [closed]
Most semiconductor manufacturers seem particular about using their own products when possible. For example, the Analog Devices Blackfin development board uses another Blackfin processor for the JTAG ...
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What IC is in this particular black blob on my pocket calculator? [duplicate]
I've taken apart my pocket calculator, and I'd like to know what IC is inside the black blob. Is there an IC commonly used in such applications?
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Simple calculator problem [closed]
So I am trying to create a calculator program in arduino using this codes.
...
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Trying to read calculator key presses into PC via parallax propeller chip
I am trying to do read the key presses from a calculator via a parallax propeller board (it's actually a DefCon 20 badge) into my computer via USB. I want the calculator to remain fully functional as ...
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Calculator with phone keypad question [closed]
I am not an electronic person and found this site in a my quest for the perfect calculator. I use both a phone and calculator for calculations and find the back and forth to cause me to make errors ...
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