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)

-3
votes
0answers
24 views

Forming Larger Decoders / Encoders

I was asked if we could implement a 4x16 decoder with different sets of smaller circuits. two 3 x 8 decoders with one 1 x 2 decoder, five 2 x 4 decoders four 2x 4 decoders and three 1 x 2 decoders ...
0
votes
1answer
46 views

How to implement a xor gate with nand gates

I try to resolve a problem, how to implement a xor gate with nand's gate. A xor B = A'B + AB' So, this becomes : A xor B = A'B + AB' + AA' + BB' = A(A' + B') + B(A' + B') = (A + B)(A' + B') = ...
2
votes
3answers
297 views

what is quadruple in IC gates

What is quadruple in integrated circuit gates? Is it just about 4 gates inside the IC or anything else more special?
1
vote
1answer
36 views

S-R latch / flip- flop question

First I want to ask, why are S and R inverted when comparing an S-R latch with NAND and NOR gate. It just seems odd to me that they're being inverted. Secondly, why is a multi-transition behaviour a ...
0
votes
3answers
67 views

How to turn continuous signal into a short pulse using logic gates?

Basically, I want to turn a continuous "1" into a short "1" pulse then "0". I'm new to logic gates, apologies if it's too obvious.
-4
votes
2answers
49 views

Logic gate with certain truth table needed

I'm making a thing in Multisim and for it to work I need a logic element which works like in this truth table: A B X 0 0 A 0 1 0 1 0 A 1 1 0 So, if B ...
1
vote
2answers
48 views

How did they get to the SR-latch with 2 NOR gates?

I understand SR latches and how they work, but I was trying to recreate the SR latch to see if I can get to the same well known circuit with 2 NOR gates. However if I write the following logic table ...
0
votes
1answer
34 views

How can I implement a K-Map with negative feedback?

How do you describe a boolean function using a K-Map in such a way that the boolean function depends on the previous value of this function?
0
votes
1answer
111 views

Building binary to two’s complement converter

This is a sample exam question, and no solutions were given I don't understand the concept of 'one bit slice', and I've tried to understand the meaning of the table, I stared at it for a long time, ...
0
votes
0answers
16 views

JK flip-flop and sequence network

State diagram of the sequence network S looks like the following for a jk flip-flop: Is this the right truth table for it? ...
1
vote
0answers
50 views

Karnaugh Map from this expression?

Here is the expression I am trying to represent in the Karnaugh Map: This is what I have done: Can somebody confirm if this is right? I have done the truth table right, however I am having doubts ...
0
votes
1answer
28 views

XOR in domino logic

I was reading about domino logic and I noticed that several resources mention that domino logic can't be used for inverting functions like (NAND, NOR) and also can't be used for XOR. I understand why ...
0
votes
2answers
99 views

What would be the output of A = 0100 and B = 0111 with S = 1 in a 4-bit binary adder-subtractor?

I understand S = 1 means subtraction and S = 0 means addition. So then, the output would be the result of 0100 - 0111. But since it's negative, I'm not sure how it would be represented. I know the ...
1
vote
0answers
48 views

Discrete logic multiplexer

I posted a more in-depth outline of what I'm doing here, but basically I'm building this circuit (for n=3): The circuit displays an output based on the combination of three three-input DIP ...
1
vote
2answers
60 views

Transition state between 0 and 1 in logic gates

Logic gates in electronics circuit works by converting analog signal into binary,say 0-3 V.Then accordingly at 0 volts the circuit correspond to low (0) similarly at 3V it correspondent to High. My ...
0
votes
0answers
19 views

How to choose clock frequency in Dynamic Logic?

I want to design a full adder using dynamic logic but I don't know how to choose the frequency of operation. I know the following about dynamic logic clock: The clock frequency is crucial for ...
0
votes
1answer
30 views

Simplest way to get a rising edge (0 to 1) for a digital input from a selectable value of an analog signal?

I'm trying to trigger an interrupt on a digital pin of a Raspberry Pi (although the question is valid for any microcontroller), based on an adjustable threshold value of an input analog signal (say 0 ...
0
votes
0answers
47 views

8 Bit Register in VHDL

I am new to VHDL programming and am currently designing an 8-bit register as shown in the picture below: Below is my VHDL code for the design: ...
0
votes
1answer
71 views

Two's Complement addition

I have a problem of adding two numbers in base of two's complement (6 bits!!!) 1100(2's C) + 0101(2's C) I notice that the first number is starting with 1 which means it's negative but since it's 6 ...
-2
votes
0answers
91 views

Operation of Logical Gate and Big Challenge

i get confusing on Digital Design Course. Anyone Could Describe why the (1) is different from (2) to (4)?
0
votes
1answer
58 views

static Hazard and challenging questions

i read some notes that wrote: for following Function F, has static Hazard, if B=C=D=1, and for each change in value of A, the Static Hazard 1 can be. Why this statement is True?
-1
votes
1answer
37 views

functionsgenerator - arithmetic logic unit

Given that If ABCDE = 11000 then S = X + Y If ABCDE = 11011 then S = X - Y If ABCDE = 10001 then S = X + 1 What should be the value of ...
-2
votes
5answers
161 views

Design Combinational Circuit

Design circuit which compares two 4-bit unsigned numbers A and B. The circuit should have one output X such that X = 1 whenever A>B X = 0 whenever A≤B You may use any MSI modules as well as any ...
0
votes
1answer
40 views

Making a k-map from an equation

I understand kmaps and I know how to make one from an equation in sum-of-products form. For example, w'x'y'z + w'x'yz. But I don't know what to do when some of the ...
6
votes
4answers
497 views

Multiplexing a Circuit

Frankly, I'm overwhelmed with this circuit that I have to start building in lab tomorrow. Last week we built an octal decoder that takes a 3-bit binary input from 000 to 111 and displays a unique ...
0
votes
0answers
52 views

Given a Boolean Function, Represent it with a 4-16 inverted decoder

The Question Given a function F(w,x,y,z) = ProductOfMaxTerms[0,4,5,6,7,9,10,11,12] implement F using one inverted 4-to-16 decoder (positive enable) and a NAND gate My Work Since it's an inverted ...
4
votes
3answers
413 views

What is race around condition in flip-flops?

I've gone through two of my text books and consulted my teacher but nothing seems to clarify my doubts. The two versions of race-around which I've been taught are - When the S and R inputs of an ...
1
vote
3answers
42 views

using a NOR gate output to a mosfet switch, improper high level output voltage

I am using a hex 2input NOR gate IC (TI SN74AS805BN). NOR Datasheet with a 5V regulated supply I want this to control a power mosfet switch Vishay FB180SA10B MOSFET Datasheet. The problem is that the ...
0
votes
2answers
35 views

Customizing Digital Thumbwheel Switches

Has anyone used a Thumbwheel Switch such as these: http://www.digikey.com/product-search/en?mpart=A7D-106-1&vendor=39 I am interested in changing the internal number strip. For examples I have ...
0
votes
3answers
51 views

Implementing a boolean function using a decoder

I am taking a course in computer organization, and currently struggling with circuits. I was stumped by the question below. I drew the K-map for the boolean function and managed to obtain a ...
1
vote
1answer
35 views

Theory for 3-bit full adder and calculations with un-/signed integers

With the following scheme, I built myself a 3-bit full adder. What I'm wondering is, and I couldn't figure this out myself, does the adder calculate with signed or unsigned values? Is the range for ...
3
votes
1answer
90 views

3.3v to 5v logic?

I have been looking over various data sheets for hours and still am not sure how to select an apporiate device. I am looking to send 5v 10ma pulses at 100-300kHz (to be determined) to a motor driver ...
-5
votes
0answers
28 views

Power and Delay calculation

I am doing project on tanner eda tool. i want to calculate power and delay for my circuit in t-spice. please tell how to calculate that one.
0
votes
0answers
32 views

How to use CVSL logic compared to CMOS to perform functions?

I am familiar with CMOS logic family and I wanted to learn about Cascode Voltage Switch Logic (CVSL) logic family. I understand following: It consists of two PDN in which they are dual. It has two ...
0
votes
1answer
83 views

Converting karnaugh maps to Boolean expressions

My professor briefly mentioned that there are ways of "taking 0's" and "taking 1's" from a K-map that allow you to form the logical expressions differently (e.g. NAND-NAND, AND-OR, NOR-NOR, etc.). Can ...
0
votes
1answer
62 views

Using Karnaugh maps to construct and simplify Boolean expressions

I'm trying to construct a circuit based on K-maps (see picture) - and I must do so only through two-level logic (excluding inverters). Some of the K-maps naturally came out in two-level logic, but ...
0
votes
3answers
75 views

This state machine does not go into an initial state on start

This is my state machine code: ...
0
votes
2answers
86 views

How to change a sum of produts using AND and OR gates to make it only use XOR gates?

I have the SOP (Sum of Products) equation: F = ¬A¬BC + A¬BC + A¬B¬C + ABC, which is the sum output of a full adder. Could someone please help me and show me how by ...
1
vote
3answers
63 views

Designing a synchronous frequency divider to 13

First post here, so sorry for mistakes or inappropriate posting. This was one of the tasks in a digital logic exam I failed today. The exact request was "Design a synchronous frequency divider to ...
1
vote
1answer
64 views

Help between 2n2222 and 2n2222a?

I am thinking about ordering this: http://www.ebay.com/itm/x100-Fairchild-PN2222A-2N2222A-NPN-Small-Signal-TO-92-Transistors-US-Seller-/171520659038?pt=LH_DefaultDomain_0&hash=item27ef6d8e5e and ...
0
votes
4answers
72 views

What is the meaning of performing logical operations on two numbers?

If we are to consider two Boolean values, the logical operations on them make perfect sense. But what would it mean to perform AND/OR/XOR operation on two binary numbers? I am learning Assembly ...
2
votes
2answers
70 views

Modelling current to remain in particular range for fixed simulation time

I am a novice in SystemVerilog. I wish to know how to model a 8-bit signal X to attain four levels for certain ranges of time. For example,let the legal values of X be from 40 to 80(40 < X < 80) ...
0
votes
0answers
61 views

digital delay, program or ic?

What options do I have if I wish to delay a digital PWM signal with a signalling speed of about 2MHz? The delay I wish to apply to this signal needs to be in the range from 0 - 2000us which must be ...
0
votes
1answer
44 views

Electronic Number Lock - Digital Electronic Systems [closed]

I've been set a Uni assignment to design an electronic number lock using a Keypad, an Electronic Control Unit and an Electromechanical Locking Actuator. It's to be based on a 4-bit binary codeword. ...
-5
votes
0answers
69 views

Implementation using NAND gates

School should be open only when the Principal is present or the Vice Principal is present, and only when the School Office is open, and only when it is not a holiday. Implement using only NAND gates. ...
0
votes
2answers
41 views

How can I convert a flow sensor's pwm output to logic level relay control?

I have a flow sensor with PWM output and I can't replace it with a flow switch due to mechanical restrictions. Is there any simple way to convert the PWM output to a logic / or analog signal and ...
1
vote
3answers
126 views

Why do electromechanical relay computers tend to use higher voltages?

So I am contemplating building a relay computer. And I have not seen any information on why one would select one voltage over another. It seems that it would be ideal to use 5V relays as that is ...
2
votes
2answers
43 views

EEPROM Write Cycle Time and Write Cycle Endurance

I have an embedded software application that is copying a buffer from RAM to EEPROM. In this case, the EPROM device is a 28C010 (128K x 8). The copying is done at non-regular intervals, generally in ...
0
votes
1answer
68 views

Realisation of asynchronous decade counter

Here is the illustration of the counter: Can you please explain in detal what happens here? Why are J and K inputs always 1 and how does CLR reset these flip-flops?
1
vote
1answer
66 views

What is the inverted output for on a D flip flop?

I was asked to find the answer for this, it is a pretty vague question: On a D Flip Flop, what is the Q' output? Look this up and write your answer in your pre-lab report. I am trying to understand ...