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7
votes
1answer
137 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 ...
-4
votes
0answers
44 views

How do I explain a binary calculator? [closed]

Could you please explain how this calculator work and give me an example more easily understood?
0
votes
1answer
48 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
182 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
83 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 ...
7
votes
2answers
1k 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
47 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 ...
14
votes
5answers
4k 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 ...
2
votes
1answer
630 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
236 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
262 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
306 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
2k views

Simple calculator problem [closed]

So I am trying to create a calculator program in arduino using this codes. ...
2
votes
1answer
214 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
363 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
415 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
608 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
285 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
713 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
183 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 ...
8
votes
3answers
2k 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
926 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
1answer
983 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
45k 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 ...