Digital electronics use a finite number of states, unlike analog electronics that treat continuous signals. Digital logic is used to perform arithmetic operations with electric signals, and constitutes the base for building CPUs.

learn more… | top users | synonyms (3)

0
votes
0answers
2 views

Implementing a 8X1 multiplexer using two 4X1 multiplexer

"Obtain an 8 X 1 multiplexer with a dual 4-line to 1-line multiplexers having separate enable inputs but common selection lines. Use a block diagram construction." This is a question i came across ...
-5
votes
1answer
27 views

How to design a Design a 64 x 8 memory using two 16 x 4 RAM chip?

Can someone suggest how I would start this project? I want to design a Design a 32 x 4 memory using two 16 x 4 RAM chip.
0
votes
1answer
19 views

(w+x)-(y+z) operation with half adder and half subtractor

I can't seem to solve this problem. Already, I'm little confused because of using half adder and half subtractor. I have tried to draw then stuck. How can I make the operation by half adder and half ...
0
votes
1answer
45 views

Designing a 4-bit binary number divider circuit

I was given homework to design a 4-bit binary number divider which divides four bits by 5 (101 in binary). I tried looking at a lot of solutions without success. All I can use are basic gates, no ...
-3
votes
1answer
31 views

Making circuit that calculates two's complement of 4 bit number

How can I make a circuit that calculates two's complement of a 4-bit number just by using 5 logic gates ?
0
votes
1answer
17 views

What does splitter do in logisim?

I have just started learning logisim, so i have a very simple question. My question is what does splitter do. Whats its function and how can we actually implement it(like on breadboard or trainer ...
-2
votes
1answer
15 views

need load / pressure sensors that can transmit digital data to an wifi receiver [on hold]

have an environment where i need to get an reading from load sensor or pressure sensor min (20Lbs)(max 200Lbs) from 10 location or more to an wifi receiver thats connected to my PC ,all these sensors ...
3
votes
2answers
164 views

How to create a frequency doubler circuit using only flipflops/ Digital elements?

First things first, is it even possible to scale up the frequency using only digital elements, atleast approximately? Though a frequency divider circuit can be designed very easily with flipflops. In ...
0
votes
0answers
37 views

Effective Address calculation time on 8086/8088

I've started designing an implementation of an 8088 from scratch with the goal of being cycle-exact. I can understand the reasoning behind the number of clock cycles for most instructions, however I ...
0
votes
2answers
51 views

how to select one logic signal between two?

I'm working on a tic tac toe project using logic gates. I'm trying to make it automated. At one point , my circuit have to get one signal (high) among eight input pin.But there will some case arise ...
1
vote
1answer
47 views

How do you design a circuit to implement the Bipolar Line coding Technique?

Bipolar NRZ http://www.tutorialspoint.com/data_communication_computer_network/images/bipolar.jpg In this technique alternate 1's will have alternate polarities and 0's will be zero itself.
2
votes
3answers
129 views

How a 8 bit Computer calculate big numbers

I'm trying to design an instructable 8bit CPU in logisim. Is it possible to calculate big numbers with an 8bit CPU? In 32bit computer, you can calculate numbers bigger than 32bit, I think it's a ...
2
votes
1answer
31 views

How does a half adder made of crossbar latches operate?

I am researching memristors, and one application that's frequently cited is a crossbar latch that sandwiches memristors between two layers of wires to form a grid. In most examples, this is configured ...
1
vote
1answer
46 views

It is better to have a negative clock skew?

Is it better to have a negative clock skew? Why? If we compare it with a positive clock skew, which is better?
-1
votes
1answer
48 views

Parity self correcting code

I am preparing for an exam in gates. I have a question regarding digital electronics. Decimal number 5 in level parity self correcting code A) 00101 B) 01011 C) 01100 D) 10000 The provided answer ...
2
votes
0answers
51 views

Sequential Traffic Light Controller

Just for clarification: I'm just looking to see if I'm on the right path for this project and to figure out what the best plan of attack might be. I'm trying to simulate a sequential traffic ...
0
votes
2answers
240 views

Designing an 8 x 3 memory chip given 2 4 x 3 chips

I'm working on a problem that asks me to design an 8 x 3 memory chip given 2 4 x 3 memory chips. I'm not sure how to approach this problem. I've looked at the textbook and found various online ...
0
votes
2answers
65 views

JK Flip Flop Counter

I am designing a counter circuit that will perform the following function: A sequential circuit with three flip-flips A, B and C and two inputs X and Y. If X=0 and Y=0, the counter remains in the ...
0
votes
1answer
56 views

Driving 50-pin e-ink display with one chip?

I'm trying to connect this 50-pin e-ink display to an Atmel ATmega328p for a hobby project. The biggest design challenge I'm facing is connecting all the pins from the display to the MCU in an ...
0
votes
2answers
48 views

Level shifting 8 output IO Expander from 0V-5V to -2.3V to +2.3V

I have a circuit problem that I'm trying to find a solution for. I have an 8 output IO expander which outputs 0V-5V. It is running analog switches which have a Vdd and Vss of +-2.3V. Using the 5V ...
3
votes
1answer
67 views

Half Adder and Two Function, A Contest Questions?

I ran into a 2013 contest question on computer-science filed. What is the following True about F and G function. (The output ...
-1
votes
0answers
47 views

Necessary tools/environment for writing VHDL RTL? [closed]

I decided to implement my own MIPS computer using Digital Design and Computer Architecture book. I decided to use VHDL since Peter Ashenden's "The VHDL Cookbook" I think is a great starting point. If ...
0
votes
0answers
15 views

Finding the State Table for a Synchronous Sequential Circuit

I'm learning about circuits in my ECE class and want to make sure that I have the correct table. I am working with D flip-flops and T flip-flops in this circuit. I want to make sure that I have the ...
0
votes
2answers
37 views

Working of 2 input AND diode register?

According to the description that I am reading in book it says that you need to connect +Vcc to both the A and B in order to get the output 1 at Q. I don't really understand this. What does the ...
0
votes
1answer
38 views

Rising edge pulse detector from logic gates

The circuits I describe are entirely made of 7400 series logic gates (7402, 7404 and 7408 ic). I'm trying to build a rising (positive) edge pulse detector using logic gates. The following circuit ...
2
votes
1answer
40 views

is the drawn diagram right for detecting a sequence of three or more 1's?

i saw this diagram in my textbook for the problem : Suppose we wish to design a circuit that detects a sequence of three or more consecutive 1’s in a string of bits coming through an input line ...
0
votes
0answers
62 views

Generating very low noise control voltage from an MCU?

I want to control the THAT Corp. 2180 VCA using an MCU. I'm using the positive VC input (it has one positive and one negative and they are symmetrical). The range that I want to generate is +/-540mV. ...
2
votes
1answer
52 views

Question about logic gate optimization and CMOS implementations

I am struggling with a conceptual question surrounding logic gates and how they're efficiently implemented in CMOS circuits. For example, let's say I want to implement a NAND gate. If I didn't know ...
0
votes
0answers
38 views

How to implement the bit count using logic circuit?

I am very interesting in these bit counting problems, since there are many programming implementations such as: http://gurmeet.net/puzzles/fast-bit-counting-routines/ Also someone discussed the ...
0
votes
2answers
45 views

K - Map essential and non-essential prime implicants

Here is the min terms for K - map simplification: F = summetion m(0,2,3,5,7,8,10,11,14,15) May i know, if i draw the graph means, what will i get Essential and ...
0
votes
3answers
104 views

Behavior of logic gates when one input is undefined?

I tried to understand to behavior of this circuit when it has no voltage supply at first which means the current state is neither 0 or 1. You can say that there is a 'nothing' input. Then when the ...
0
votes
0answers
24 views

SR Flip-flop builded from 2 SR-Latch

I just study about flip-flop in my class and this is the picture from the slide my teacher used that explain the construction of SR Flip-flop However, I find something was wrong with this figure. ...
0
votes
1answer
19 views

How to properly check/evaluate Multiplexer design implementation?

I am not electrical engineer at all. I am just participating in this course. I have been struggling for 2 days to implement Mux8Way16 - a multiplexer which has 8 different 16-bit inputs. How can I ...
-1
votes
1answer
39 views

how to minimize the product of sum from canonical pos?

I have a canonical pos form which is derived from SOP by using demargon law. POS: (A+B+C) (A+B+C') (A+B'+C') So i need to reduce this to min pos. May i know, how to get like this form (A+B) ...
3
votes
3answers
96 views

Logical Design Operation, A Simple Questions?

I'm so sorry if I ask my first question that so simple. My filed is Math and Computer science. I self-study Digital Design. My challenge is how we can find the operation of the two following ...
1
vote
2answers
54 views

Finding number of don't care conditions

I'm new to these forums and have very little background in electrical engineering. I'm trying to figure out the number of "don't care conditions" based on an input of two numbers, each 0-9, for ...
0
votes
1answer
35 views

Code Converter Circuit

Make a BCD to Excess-3 Code Converter by using a binary to decimal encoder and 4 OR gates. I know how to make a binary to decimal encoder, but how do I proceed from there?
-1
votes
1answer
56 views

Calculate a function with logic gates

I have to build a circuit, with logic gates, that calculates a function \$f(n) = 2^{2^n}\$ where n is a 4 bit number. I can't figure a way how to do this. I tried to use 2-to-4 decoders but I failed. ...
-1
votes
0answers
27 views

arduino detech signal from bike pickup coil

I want use the arduino detech signal from bike pickup coil for calculate rpm and delay ignition. Should I use a good circuit? I just started the electronic Thank you
1
vote
2answers
45 views

Detecting HI-Z state of charge controller

I have been building a Li-Ion charge controller with MCP73831. The STAT pin has 3 states as shown below: The circuit I come up so far is this: Is there a way to detect the HI-Z state with ...
1
vote
1answer
34 views

Design a Decoder using Logic Gates to display letters on a 7-Segment Display

The task I got is to design a similar circuit to a standard BCD to 7-Segment decoder, except only using Logic Gates and to display a eight letter character word, for example: SHELFLES As I have ...
2
votes
7answers
1k views

Why are 11, 111, 1111, … equivalent to -1 in two's complement? [duplicate]

According to two's complement, the binary numbers 111 and 11111111 are equivalent to -1. Why or how are the binary numbers 11, 111, 1111, 1111 1111, etc. equivalent to -1 in two's complement? Can ...
0
votes
0answers
27 views

4-to-10 Decoder truth table

I was given in a lab a 4-to-10 decoder truth table. I was wondering why it stops at 10 inputs. However, my circuit could hold up to 15 instructions. So for instance, I built my circuit and it went ...
0
votes
1answer
34 views

designing a sequential circuit by having it's value table?

when learning about combinational circuits we could draw the truth table and construct a circuit by the help of min/MAX terms . and we could further simplify it with Karnaugh maps . BUT how we do ...
1
vote
2answers
41 views

How Verilog decides upon simultaneous events

Say we have a function, simple as f(x) = x. Say we have a clock that ticks every 20 nanoseconds, and say we change x as we wish. ...
-2
votes
5answers
120 views

Is sequential logic really required to solve some types of problems? [closed]

Can all digital design problems theoretically be solved using only combinational logic, or are there specific examples that have to be solved sequentially? I read that sequential logic is only ...
0
votes
0answers
28 views

Analog to digital converter for PIC18F2420

I am trying to get digital value in PIC18F2420 from analog input. The analog input is connected to RA0 port. Following is the code. I am getting 0 value for my interger "myvariable" when i look in ...
0
votes
1answer
50 views

Insight on analog and digital Lock-in amplifiers operation principle?

As far as my knowledge goes, in the analog case, the discrimination of the, low S/N ratio, signal is done by (demodulation) comparing it to local oscillator with almost identical frequency and then ...
3
votes
3answers
169 views

Why All 1's used as a second input in decrement operation of ALU?

Suppose the first four data inputs are X (X0, X1, X2, X3) and the second four data inputs are Y (Y0, Y1, Y2, Y3) in a 4-bit ALU. Why "All 1's" are used as an input for Y in the decrement operation of ...
0
votes
3answers
120 views

**Solved** D Flip Flop Frequency Divider - Simulates but doesn't work on protoboard *Pics/Simulation Data Included*

I'm having a problem that is probably trivial, but I can't seem to make any progress. Just a disclaimer, I'm an analog EE and digital design isn't my strong suite. That being said, I'm trying to build ...