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Questions tagged [calculator]

The tag has no usage guidance.

5
votes
2answers
674 views

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 ...
0
votes
1answer
46 views

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 ...
0
votes
3answers
123 views

How to build 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, ...
0
votes
1answer
218 views

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 ...
3
votes
1answer
192 views

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 ...
1
vote
2answers
185 views

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 ...
0
votes
1answer
161 views

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 ...
0
votes
3answers
1k views

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 ...
0
votes
1answer
165 views

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 ...
0
votes
4answers
613 views

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 ...
1
vote
3answers
2k views

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 ...
0
votes
2answers
175 views

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 ...
4
votes
4answers
682 views

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 ...
-1
votes
4answers
207 views

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 ...
0
votes
2answers
594 views

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. ...
1
vote
1answer
212 views

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 ...
0
votes
2answers
245 views

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 ...
1
vote
1answer
7k views

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 ...
9
votes
4answers
749 views

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 ...
2
votes
3answers
393 views

“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 ...
16
votes
1answer
674 views

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 ...
0
votes
1answer
232 views

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 ...
-2
votes
1answer
792 views

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 ...
1
vote
3answers
1k views

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 ...
9
votes
2answers
6k views

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: ...
1
vote
1answer
132 views

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 ...
19
votes
5answers
8k views

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?
10
votes
3answers
2k views

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 ...
3
votes
1answer
2k views

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 ...
-1
votes
1answer
430 views

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 ...
-2
votes
2answers
595 views

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 ...
2
votes
1answer
816 views

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?
0
votes
1answer
3k views

Simple calculator problem [closed]

So I am trying to create a calculator program in arduino using this codes. ...
2
votes
1answer
301 views

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 ...
-5
votes
2answers
468 views

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 ...
0
votes
2answers
906 views

Calculating “useable amps”

We use a 1650 mAh capacity LiPo battery. It has a 2.5volt undercurrent protection cutoff set. Our device uses a CONSTANT 5mA of draw UNTIL the battery drops down to 3.2V, at which time the system ...
-2
votes
2answers
876 views

how can i connect my usb port to ATmega16

I have a calculator circuit and i want to be connected to pc with a USB port,this circuit contains a ATmega16 micro,my question is how can i see dats that keypad sends in both calculator lcd an pc ...
0
votes
2answers
508 views

How to design voltage ladder on ADC for non linear purposes

I'm designing a 4-bit ADC for a project that receives a reference voltage that ranges from 1.0 to 1.25. The problem is, it's not a linear variation, as in 0001 can be 1.05V, 0010 1.1V but 0011 could ...
-3
votes
2answers
931 views

Arduino 3 digit LCD calculator

We would like to build a calculator using Arduino which uses 3 digit LCD and a keypad similar to digital phones. (# for plus , * for minus) Which components and way is good enough to not to run out of ...
1
vote
0answers
319 views

Impedance calculators differ pretty much?

As you can see here to calculators I found show huge difference or didn't I set it up correctly? I didn't found hints on possible validity limits. Can someone say if one of those given out results is ...
8
votes
3answers
3k views

Designing a simple ALU

I need to design an ALU with two 8-bit inputs A and B and control inputs x, y, and z that supports the following operations: ...
3
votes
2answers
1k views

What exactly is happening when a graphing calculator LCD malfunctions when batteries are weak or overloaded?

I'm a beginner in electrical engineering, and I have limited knowledge of how electronics work internally. I'm trying to understand some odd LCD behavior when the batteries are weak or subjected to a ...
1
vote
2answers
2k views

How to calculate Vout in this resistors network?

How do I calculate Vout in terms of Vin and R1,...R5? Vin----+-------+ | | R4 R1 | | +--R5---+--Vout | | R3 R2 | | ...
15
votes
12answers
68k views

How to build a calculator?

I'm a newbie in electronics. I'm trying to build a calculator from scratch as a simple project and side hobby to keep me busy. My goal is to build a simple calculator, not a scientific or graphing ...