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.

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How to switch between two input lines based on a digital pulse

How can I switch between two inputs based on a digital signal. I would like to have the Input 1 connected to the Output for the duration of the pulse and Input 2 connected to Output when the signal ...
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1answer
43 views

NAND gate in proteus

I am trying to make a JK flip flop circuit in proteus but 2 of the nand gates does not seem to be working. There are no errors provided. Two of the 2-input nand gates does not seem to show output ...
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1answer
61 views

H Bridge Control using Raspberry PI / Micro controller

I am looking for input on this circuit that I have designed. I am currently working on a project called the Net-EEL RC Car. It is an RC car that will be controllable using Network Socket Servers / ...
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1answer
58 views

Shift Register Vs Multiplexer

I am not sure about an implementation. I've a multiplexer 8 input, 1 output and 3 select signal. One of these selects signal sequentialy acquires all value of a bit vector. Now I can choose 2 way. ...
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4answers
82 views

Two's complement maximum and minimum

If we have a binary sequence that is \$x\$ bits long, what are the minimum and maximum that can be represented in two's complement form? The maximum is \$2^{x-1}-1\$, and the minimum is \$-2^{x-1}\$. ...
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1answer
57 views

Using a Counter to Determine next MSB position in polynomial division

I am working on implementing a polynomial divider the operation is as follows: Check MSB of Numerator: if 1 XOR with Denom then shift Denom right if 0 Num is the same and Denom also shift right When ...
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1answer
58 views

Convert this to standard POS

Can you please help me converting following to standard POS A(A + C')(A + B) Thanks I have done the following so far ...
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5answers
96 views

Understanding D flip flop function - what this thing does

I am trying to understand what a D flip flop does int he context of building a truth table, so I can design a synchronous divide-by-five circuit. That is, count to five and reset. I know I need 3 ...
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2answers
54 views

Unable to toggle SN74HC109

I'm a complete amateur, I've probably gotten a million things wrong with this already. I'm using an SN74HC109 dual j-k" flip-flop chip. I'm trying to toggle the led (forgot to add a resistor in the ...
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1answer
1k views

Why use a 0 ohm resistor? [duplicate]

My customer's schematic uses a 0 ohm resistor for connecting analog(AGND) and digital (DGND). I think it is for testing, current measurement , fuse, jumper, test point etc but is there another ...
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1answer
51 views

JK Flipflop design for conveyor project

I have a small project/problem I am working on. While running a conveyor belt continuously with items on it, I need to stamp every other item. I am using a photocell to detect if an item is ...
0
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2answers
53 views

Transistor Based NOT Gate Not Working?

I Followed The Following Circuit For The Logic NOT Gate from This Website http://www.northdownfarm.co.uk/rory/tim/basiclogic.htm Here is My Circuit Which is Intended to Perform The NOT Function ...
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3answers
45 views

SN74HC138 demultiplexer. How do I implement a switch?

I have this demultiplexer and I need to configure it in such a way that I can control 8 transistors using its outputs. They NEED to be NPN transistors, so when I select an output using the addresses, ...
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0answers
53 views

How to draw a state diagram with following specifications?

I want to draw a state diagram with the following specifications: *  The input is 0 and 1 and the first MSB bit is received *  Whenever the number of "11" and "0" ...
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1answer
45 views

Single regulator to power mixed signal PCB?

I have a codec (ADC & DAC) with both analog and digital power and ground connections (upper half is analog, lower half is digital). By placing the device package in such a way that all digital ...
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3answers
33 views

MOSFET chip for discrete CMOS inverter

My plan is to build a discrete CMOS inverter(just out of curiosity) out of two complementary MOSFETS. Hence, I am currently looking for a nice pair of complementary MOSFETS, which is quite hard, ...
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1answer
39 views

The difference between algorithmic state machine (ASM) and state transition graph

I have a very basic question. In what ways an algorithmic state machine (ASM) is different from a state transition graph (STG). Can someone take a very basic example (such as a binary counter) to ...
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1answer
42 views

Breadboarding digital mixer: deriving Vref from Vdda, and capacitor between Vdda and Vssa?

I am assembling a digital audio mixer from an old IC I have on my workbench. And I am reading the data sheet and trying to make sense of a note that describes the Vref pin (reference voltage). The ...
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1answer
49 views

Building a 2-bit adder with a propagation delay of at most 2 gates

An XOR-gate itself counts as 2 gates, so if I use an XOR-gate the delay would already be 2. I have no idea how to do this, as a full adder for one bit already contains 2 XOR-gates (or 1 XOR-gate, 1 ...
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0answers
26 views

MEMS Accelerometer/Gyro 3-axis Conversion question

I'm not too familiar with the digital mems signal to analog conversion using a microcontroller. Can you still retain the signal intensity due to rotation of the gyro, or is the output always going to ...
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1answer
52 views

Sequence detector

I have a few questions to ask about electronics.I am studying computer science in my first year and I have a logic design course where the professor is kind of old let's say and he expects us to study ...
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0answers
31 views

Introdution to CUPL with Example?

I want to introduce with CUPL programming but i need a example.for example if i write a hex bcd to 7 seg decoder how i write it in CUPL?(I can write it with verilog but i want it into CUPL)
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4answers
507 views

Construct an AND gate from XOR gates

I was able to figure how to make a NOT gate easily enough, but I'm stumped trying to figure out how to make an AND gate. Is it even possible?
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0answers
30 views

Hint for design

I want hint to design below circuit: design a circuit with 74LS164 and 74LS161 and a BCD/7 Seg Decoder that 7 seg indicate number of ones of a binary number.
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2answers
104 views

How do FPGA's implement sequential circuits?

I know they implement combinational circuits using LUTs, but LUTs don't have feedback, so I don't see how they can be used for sequential circuits. So how do FPGA's implement sequential circuits? ...
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2answers
70 views

Data Whitening Block Diagram

I would like to understand this block diagram and how it relates to the formula: g(D) = D^7 + D^4 + 1 Supposedly this helps to generate a whitening word used within bluetooth radio, the empty boxes ...
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2answers
77 views

Design a 4-bit PISO shift register with 4 DFFs and 3 AND gates

I want to design a 4-bit PISO shift register with 4 DFFs and 3 AND gates. I have gone so far that these two designs can be implemented, but I can't go further minimizing it so as to use 3 AND gates ...
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1answer
34 views

How can I use an IO ports on Digilent Genesys Virtex 5 to drive 6 external leds?

I have a project which requires led output. Right now I'm using the onboard leds, but I would like to use 6 external LEDs instead. Which IO pins should I use, and how should this be done? I'm ...
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1answer
163 views

How do I analytically list the correct sequence for the given digital circuit?

Suppose given the digital circuit below, which contains 3 JK flip-flops: Assume that the sequence starts at ABC = 000. How can I analytically list the resulting sequence after every clock cycle?
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29 views

MCP23017 not causing interrupts using a normally open switch on power up

I'm working on a project where I am using two 4x4 button pads. I would need to use two MCP23017 for input interrupts to support the 32 buttons. I am using a Netduino and I'm coming across an issue ...
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10answers
4k views

Is there any way to use half-bits?

As most people here know, by using 4 bits, we are able to count from 0 to 15 (0123456789ABCDEF in hexadecimal). But if we were to only count up to 9, we would still be using 4 bits, and the digits ...
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0answers
32 views

How to implement a pipelined integer divider

I need to implement a pipelined integer divider for my 64-bit microprocessor. I have tried reading up on this, but I am still confused. Any advice would be appreciated.
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6answers
242 views

How to implement an 8-bit CPU?

I'm trying to create a CPU, using 8-bit instructions, and there will be 9 or 10 of them. I have an add, subtract, multiply, load, store, branch if zero, branch if not zero, print (to display), input ...
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2answers
113 views

Lots of thermistors but no readout

Back in Sep '12, Olin Lathrop answered a similar question about wiring a digital display to a thermistor, but my situation is slightly different from Jim McDerby's. I too have solar thermal panels ...
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2answers
64 views

How to Design D flip flop using T flip flop?

I don't know how to convert flip flops to each other but i know with any flip flop you can make all other flip flops.Please help me to how design it with specific way and explain step by step.Are ...
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1answer
37 views

How to calculate logic gates power in microwatts in Matlab?

I am designing a circuit in Matlab2014 Simulink using logic gates and I am giving Pulse and Constant at the input of the circuit but I cannot measure current and voltage at the output of the circuit. ...
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0answers
37 views

Digital to analoge voltage regulator

I am a complete beginner on electronics. I am trying to make device to control the voltage output according to a digital input. So basically what I need to make is to continuously increase the ...
2
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2answers
261 views

Why is shift register very important?

I learned about shift registers a few weeks ago but I don't know why it is very important and everyone said that it is necessary for microcontroller, etc. Please make sense for me.
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1answer
70 views

Is there relation between logic chip names and their internal structure

I know that for instance an ATMega328 is a 8 bit MCU with 32k of program space, the same can be said for most other MCUs and some other ICs with a direct relation between the name and internal specs. ...
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0answers
60 views

Arduino Output to 24V logic

We are testing out some analog sensors, and we need to send a 24V trigger (maximum 15mA) to a PLC from an arduino. I have seen some designs using a MOSFET to make a bidirectional logic converter, but ...
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1answer
72 views

Transistor count in NAND or NOR implementation of boolean algebra?

I have a complex output function in boolean algebra ( Where '~' means NOT): F=~( (a c ~d) + (a ~c ~d) + (~a c) + (~ a c d) + (a c ! d b) ) I know this can be simplified down to: F = (~a ~c) + (a d) ...
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1answer
61 views

What are “consecutive input pulses”?

I am stuck on a homework problem that I have difficult time understanding: Draw the state diagram of the circuit described below, with detailed explanations: A detection circuit has two ...
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2answers
219 views

Constructing decoder 5/32 using smaller ones, without enable

I need to construct a decoder 5/32 using any number of 2/4 and 3/8. How do I start? With Enable it's not hard to figure out, but without them it gets complicated. Advice?
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0answers
58 views

Which logic gate arrangement would be better?

I have converted an old ATX PSU to a portable power supply for traveling as it is reasonably small. To go with it I will also make up a visual indication as to the state of the PSU once on, this is to ...
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3answers
397 views

IC takes no input (or high) as high and low input as low on breadboard

I was working with IC 7400 (or LM74LS00 / NAND) (and IC 7486 - XOR) to design and verify combination circuits and logic gates. Consider the lower end of breadboard as LOW (connected to GROUND) and ...
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1answer
83 views

Finding Critical Path of Combinational Logic

I have a combinational circuit and I would like to find its critical path in design compiler. Essentially, I want to find out by how much the combinational logic will reduce the maximum clock ...
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0answers
40 views

How can I connect this ram-ish memory layout

In the picture on the web, I want to connect the two inverters that are ringing around each other, I want to connect them to the data-line. I can't seem to figure out how to properly connect them in ...
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2answers
80 views

How can I add sounds to my logic probe?

I am a beginner at electronics and I want to build a simple logic probe for TTL circuits. I found this diagram online: Which does exactly what I want. However, I would like to make it play a high ...
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1answer
95 views

What does a double array do?

While looking through some Verilog code, I came across this: input [7:0] data [0:16] The code referred to this as memory. Could someone explain what it does? I ...
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1answer
40 views

Howto convert “0=floating / 1=Vcc” to CMOS compatible “0=ground / 1=Vcc” signal

I'm playing around with CMOS logic using CD#### dip packages. As far I understand input pins should never be left floating, always connect them to Vcc or ground. Unfortunately my digital source ...