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.
2
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2answers
123 views
Equivalent of IC4026
I have tried to make a reaction timer using IC 4026. But due to unavailability of IC 4026 I want to replace it. Can I use 4017 instead of 4026?
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1answer
84 views
Beep patterns generator
I would like to generate the following beep patterns using a piezo buzzer:
Single long beep
Two short beeps
Single short beep
Is there any specific chip I can ...
0
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0answers
33 views
How ALU Perform decrement operation using LOGIC Zero
I google many ALU Block diagram for decrement operation.all same as shown below.
This 1 bit alu perform 8 operation depending upon select line status
Theoretically all operation seems works ...
0
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1answer
29 views
Initial state of SN74AUP2G80 dual FF
My understanding is that a basic FF will in general power-up into a meta-stable state that then resolves to either H or L (more or less quickly).
My question is, does this apply to current ...
0
votes
1answer
65 views
n-channel MOSFET source load alternative
I'm trying to drive some RBG leds using MOSFETS. Let's say I have 2 individually RBG LEDS, each controlled by 12V, with each R, B and G with its own output to GND. What I want to control, is to be ...
-4
votes
0answers
42 views
what is the meaning of Vtt voltage [duplicate]
i am using a digital counter ic which supports differential clock input .
the differential clock input can be made compatible with a sine oscillator output using an ac coupling circuit .
in the ac ...
1
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2answers
83 views
What is the meaning of Vtt
I was looking at the data sheet of a counter IC and the connection circuit diagram showed two connections: Vbb and Vtt
What do ...
0
votes
1answer
52 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 ...
0
votes
1answer
26 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 ...
0
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0answers
29 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 ...
1
vote
0answers
43 views
what is the approach to design edge triggered d flip flop? [closed]
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 ...
2
votes
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.
...
1
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5answers
494 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 ...
0
votes
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 ...
0
votes
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 ...
0
votes
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 ...
1
vote
2answers
218 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 ...
1
vote
1answer
79 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 ...
3
votes
5answers
815 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 ...
2
votes
0answers
72 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 ...
0
votes
3answers
96 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 ...
0
votes
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 ...
0
votes
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 ...
0
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0answers
47 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 ...
2
votes
2answers
296 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 ...
1
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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 ...
6
votes
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 ...
4
votes
2answers
93 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 ...
-3
votes
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?
4
votes
1answer
122 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 ...
1
vote
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 ...
1
vote
1answer
69 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 ...
1
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5answers
153 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 ...
0
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0answers
28 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 ...
1
vote
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?
0
votes
0answers
25 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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votes
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?
0
votes
1answer
42 views
1
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3answers
160 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 ...
0
votes
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 ...
1
vote
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 ...
0
votes
2answers
78 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 ...
7
votes
1answer
112 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
votes
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 ...
0
votes
4answers
113 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? ...
1
vote
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. ...
1
vote
3answers
160 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 ...
1
vote
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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votes
2answers
51 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
vote
1answer
30 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 ...
