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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45 views

Single Die Roll Counter Wrap Around Nested Ternary Conditional

I have to emulate a single die roll, therefore it needs to wrap back to one at 6. `D1 and `D6 correspond to my 3-bit state ...
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1answer
24 views

Minimum cover for this K-MAP to find minimum SOP; which is better, and why?

I used this K-MAP to find the minimum sum-of-products expression for this collection of minterms. I see that minterm-one could also have been "covered" by grouping it with minterm-five. I opted to ...
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0answers
27 views

Trouble analyzing this JK-Flip-Flop (negative edge triggered) timing diagram

Can someone check to see if this timing diagram for a negative-edge-triggered flip-flop looks correct? I see that as it's negative-edge triggered (bubble at clock input), and thus action occurs at ...
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0answers
39 views

what is the approach to design edge triggered d flip flop? [on hold]

i know the circuit. I implement it using verilog and it giving result correct. like when we have to design any digital circuit we draw truth table. Optimize circuit using K-map and then implement. In ...
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1answer
91 views

What is “Input high voltage common mode range?”

I am using a MC100EP016A IC which is an 8-bit synchronous binary up counter. According to the specifications of the IC, you could use either single ended or differential clock input for the counter. ...
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5answers
474 views

Very high speed counter (around 1.5 GHz to 2 GHz)

I am thinking of a device that can measure the distance of an object from a sensor using a radio transmitter and receiver pair. I'm thinking of using a counter at the sensor side, with a ...
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0answers
64 views

Very high speed counter (2GHZ) [duplicate]

I'm trying to build a high speed counter to measure the time delay between two radio waves . I'm thinking of using a MC100EP016A counter which works at a maximum frequency of 1.4 GHz but I cannot find ...
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0answers
23 views

Verilog Concatenation Setting LED'sin casex

If I have a casex statement and I have something such as {`idle, `left}: {next, LED} = {`state1 ,`turn1liteON }; and LED corresponds to LEDR[7:0] and ...
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2answers
86 views

Draw a finite state machine for a welding machine

I am trying to draw a fsm for a welding machine. So far I have the following table, which I think is right.. The system has three normal states: stopped, started, and welding. It will only transition ...
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2answers
214 views

Circuit to keep two LEDs on when buttons are released

I am trying for the first time to build something on my own. I am pretty n00b when it comes to electronic so, please, bear with me. I'm trying to build a "simple" schematic that goes like this: there ...
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1answer
78 views

Is it safe to use a bus buffer as level shifter?

I am currently using SN74ABT5402ADW as a buffer and level shifter for my ADC, however, the datasheet does not explicitly say that it can be used as a level shifter. I provide it with 5V power, but the ...
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5answers
804 views

Can an operational amplifier circuit be made entirely out of diode Nand and Nor gates?

I'm not sure whether this question has been asked before, but in researching my question, I came across this user's post (at If-else decision structure using op amps or any other non-programmable ...
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0answers
68 views

What is bit-true implementation

What is bit-true implementation (with an example if possible)? I was reading a paper and it was stated "a bit-true implementation of the algorithm on a FPGA was performed." So what exactly is ...
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3answers
95 views

Should I use CMOS vs. TTL?

Now, I know that this question has been asked so many times that it seems like I'm trolling, but I must point out that I couldn't find the right answer to this question anywhere. So yeah, CMOS and ...
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1answer
42 views

fpga verilog dual access

I need to write to a register from 2 sources.. in this case, a pci host and a microcontroller. The 2 will never access the register at the same time (basically once the PCI is done , it hands it ...
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1answer
42 views

Registers and Busses

I need to design a schematic for a register that has an input of clk and i[7:0] which is an 8 bit binary input interpreted as a number and an output of F which goes high if i was equal was to 127 base ...
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0answers
46 views

Can you calculate parasitic elements caused by using many breadboards?

Recently, I've had the idea of building a 4-bit CPU out of RTL (Resistor Transistor Logic). Because there are so many connections, I would prefer to build this project on many breadboards. I realized ...
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2answers
295 views

I/O series resistor

I've read that digital I/O pins should have a resistor in series in order to limit noise. Should one also use such approach when interfacing with the I/O pins of an arduino, or is that already done on ...
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1answer
54 views

Digital light organ

I am trying to make a circuit that takes an audio signal from an MP3 player and converts the signal into digital signals based on frequency. Audio In is the is the signal from the audio jack of an ...
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6answers
1k views

How does a non-FPGA (ie a PC with a CPU, RAM, hard drive) mimic logic gates?

I know that an FPGA uses look-up tables (LUTs) to synthesize logic gates. A LUT is a block of RAM that is indexed by a number of inputs. The output is the value stored at that memory address. The ...
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2answers
91 views

Isolating an analogue input using ADC/DAC

I'm looking into isolating an analogue input coming from field equipment and interfacing to a PLC analogue input module. The input will be of the 4-20mA range (1-5V). There are a few ways to approach ...
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1answer
48 views

How can I measure a three phase current using a digital multimeter?

My multimeter does not have provision for AC current measurement. Can I use a CT with my digital multimeter to measure three phase current? If so, how can I do it?
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1answer
121 views

What is this quadruple triangle logic symbol? [duplicate]

Or maybe it is two mirrored triangles... and an 'invertor' dot? This is from a diagram in the ATMega328P datasheet, page 76 bottom left. Note that this question shows a similar device. In that ...
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1answer
63 views

How does digital patch memory work on an analog synthesizer?

Not an electrical engineer, but kicking around ideas for a polyphonic analog synth with digital memory, a simplified/modernized update of an older all-analog design. I've riffled through some of the ...
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1answer
67 views

What is the ideal resistance for a 2N3904 base resistor value when using RTL logic?

I have a ton of 2N3904 transistors and would like to use them for my RTL logic project. Based on what I could figure out on the web, and the parts I had, I've gotten logic gates to work quite well ...
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5answers
152 views

Kinds of Feedback

"Feedback is a process in which information about the past or the present influences the same phenomenon in the present or future" I find the idea of feedback quite fascinating and i could ...
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0answers
27 views

conformal renaming rules: Mapping

I had around 140 extra points which were unmapped after mapping key points. Signals have this format signal[5] -> signal_5_0 abc[5]_z -> abc_5_0_z So I ...
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2answers
66 views

Fan in Fan out problem

Fan out is the maximum number of inputs that can be connected to a specific output. Why can’t we connect more number of inputs to this output?
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0answers
24 views

Timing Issues When Interfacing with E28F800 Flash Chip

I'm trying to interface with an E28F800 via an Arduino Mega and am having trouble trying to program it. I'm successful in reading off the chip by toggling CE# & OE# while asserting an address, but ...
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0answers
20 views

Can a retroreflective sensor detact a Charged coupled/CMOS /digital camera?

I am working on a research project and just wanted to know if a retroreflective sensor detect a Charged coupled/CMOS /digital camera?
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1answer
42 views

Finding the minimum switching expression for this output

Did I do this correctly? ...
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3answers
157 views

74154 4 to 16 decoder logic diagram

Will someone please explain the purpose of inverting the outputs (0 through 15) as well as the use the NAND gates here? 2nd, less important question: why are there two input G1 and G2 if the ...
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3answers
74 views

In a NOT gate circuit, does charge not flow through both the transistor and output line when the transistor is “on”?

I've tried to recreate a circuit from what I think would be a NOT gate, based on some other schematics and breadboard examples that I've seen. simulate this circuit – Schematic created ...
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2answers
110 views

What's the point of putting two NOT gates sequentially? [duplicate]

I found the following diagram in data sheet for M74HC595 8 bit shift register I have three questions. Do I understand correctly that all blocks inside red ellipses are NOT gates? What is the ...
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2answers
76 views

Are NAND Gate Pinouts a Standard?

I have this really old NAND gate that I need to replace. As you will see, the datasheet is worthless and it is the only one that I can find. This is my first experience using a NAND gate (I ...
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1answer
109 views

How do I debug red signals in ModelSIM?

I have to design a state machine using only NAND gates for the combinatorial part and D flip flops for the sequential logic. Everything should run at a clock of 1ghz/53. Now before you assault me ...
0
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1answer
22 views

how to simulate 4 bit ring counter using max+plus II

I'm newbie with max+plus II and digital modelling world just want to simulate a simple ring counter https://www.dropbox.com/s/47tlv3g7o9zi8gb/all.jpg the ring counter's initial value must set to 1 ...
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4answers
112 views

What are logic gates?

So from what I understand transistors are one of the most important electronic elements for computers because of TTL (Transistors-Transistors Logic). Is this true? If so, how exactly does this work? ...
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0answers
73 views

Digital Latch Circuit with Unknown Outputs

Introduction I am a student currently enrolled in a digital course course. I'm actually an analog kind of individual so I (like most other analog people) have a hard time understanding logic. ...
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3answers
157 views

What is the best transistor for a large RTL (resistor transistor logic) project?

I've been reading up on older computers like the PDP-1 and TX-0. I'm fascinated with them and love the idea of making a CPU of my own using discrete resistors and transistors. Keep in mind, this is ...
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2answers
42 views

Expression and gate not gate output

The expression I came up with this circuit is A'B + A'CD + C, would the output change to AB' + AC'D' + C' since it is inverted? I'm assuming the D input compliments and cancels out? What would the ...
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2answers
50 views

Understanding circuit : Output of a CD4017 with 1N4148 diode and RC circuit

I'm reading a circuit on a magazine (look at circuit below) and i don't understand , why the author put a 1N4148 diode and a RC circuit at the output of CD4017 , what is the operations of the RC ...
1
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1answer
27 views

Multi-input AND gates from 2-input AND gates

To realize a 3-input AND gate from 2-input AND gates, we need 2 such 2-input AND gates. Assuming we have infinite supply of 2-input AND gates, can we obtain a general formula for the number of 2-input ...
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2answers
110 views

An exercise on decoders

I have the following exercise: Design a circuit that takes a 2 bit binary and makes it x^3 (x cubed), using a decoder of your choice. I thought to do it with a ...
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1answer
70 views

Differential signal processing and generation

I am trying to interface to a Mitsubishi central aircon unit. Based upon the manual, the internal units communicate over a differential bus (I hope is TDM). I have a screenshot of the signal: How ...
1
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1answer
32 views

Real Time Data Capture System

I would like to build a system which could capture an analogue waveform data in real time. For the basic data acquisition system I can use an ADC to digitise an analogue waveform and store this in a ...
3
votes
1answer
76 views

Show numbers on LEDs

I'm a beginner in EE, so maybe the following question seems obvious to you. I have to design a circuit that get a number from 0 to 9 via a decimal keyboard, and then show the corresponding number on a ...
5
votes
2answers
1k views

Karnaugh Maps - What is the purpose of a “don't care” condition?

I've got a problem and was stuck for whole day.. I'm designing an octal to 7 segment common cathode decoder which only octal digits 2 to 7 are applied to the inputs of the decoder so combination for ...
2
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2answers
61 views

Dynamic Logic - Transistor Sizing

If we have a circuit in dynamic logic: What should the size of the charge transistors (Qe and Qp) be? I know that increasing the size improves the speed but also increases the dissipation, and that ...
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1answer
78 views

Arduino PWM pin vs digital pin PWM simulation

Do I understand it correctly from this thread, Why do some pins have `~` signs next to their numbers?, that the PWM pins generate a square wave signal independently from what the code uploaded to the ...