A multiplexer selects one of two (or more) inputs based on a control input. It then outputs the selected input.

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Multiplexer Timing

I have a 4 to 1 mux that receives its data inputs and select inputs from edge clocked shift registers . Also the output of the mux goes to another shift register(call it the output register) as well. ...
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51 views

Do we ever need to use multimeter's transistor current gain measurement feature?

Many cheap multimeter have this feature that they can measure the hfe of a NPN or PNP transistor. Does anyone ever need to use it? I mean, when we design something using discrete transistors, we look ...
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41 views

What is the function of multiplexer boolean expression?

Here is the image of multiplexer: May I know, what is the output form of Boolean expression, how it is working function? Can anyone help me to guide me? Any help would be highly appreciated,
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17 views

Relation Between 8:1 Mux Signal , Mux Accessing Time & output of Mux

I have asked a question yesterday . Now i have a strange issue. I am working with Beaglebone white in Android platform . I have one external ADC (ADC121C021CIMM - connected through 8:1 Multiplexer ...
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4answers
101 views

Why would anyone use an inductor on a mux?

I read a schematic where it has a Z80 CPU tied to a 78LS138. The CPU's WR line is tied to ...
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1answer
137 views

Relation between ADC register value & ADC accessing time?

I don't have any Electronics background.I am Software Engineer. I want to know that is there any relation between accessing the ADC buffers with a time (T ) & the ADC buffer values. I am working ...
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3answers
104 views

Is there a Multiplex with X inputs to control X outputs?

I want to use a multiplex to controll my circuit. I just want something that can be a switch between an input and output. I thought to create this circuit: simulate this circuit – ...
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2answers
133 views

Can we send multiple signals in same core at the same time in the fiber optics? If yes, how?

I am curious to know how exactly does the fiber optics works. I understand the basic concepts of the fiber optics communications but am curious to know if there is a way to send multiple signals in ...
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1answer
48 views

Level translation and multiplexer

I have one logic 3v3-input (5v non tolerant) on my microcontroler and I want to interface 4 5v-inputs. So my idea was to connect a multiplexer supplied in 3v3 but I have seen in datasheet (for ...
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46 views

Implement a Boolean function using an 8x1 deMUX

Using a 1x8 deMUX with an AND gate, create F(x,y,z) where F has minterms at 1,3 and 5 This is the solution I came up with: I'm pretty sure this solution works, but it doesn't quite fit the ...
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1answer
73 views

Multiplexing analog signal

I want to read 4 analog signals (coming from 4 pH sensor, generally said 16HZ freq.) With one buffer op-amp circuit going into a single ADC channel. Is it possible to achieve this using analog MUX ...
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1answer
50 views

How to deal with analog pin drivers with output switching?

I'm trying to figure out if there's any way to affordably improve the performance of an analog pin driver that needs to be periodically isolated from its load, for the duration of self-calibration. ...
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Individual Control of 4 DC Motors with 1 Motor Driver

I am trying to control 4 DC Motors with a position feedback signal, with access to only one of manufacturer's motor control driver boards. Since I don't need simultaneous control over all of them, I ...
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1answer
45 views

Current sourcing octal buffer/line-driver for 7+1 segment LED multiplexing?

I would like to multiplex 8, 7-segment LED displays with two, 8-bit shift-registers. The required current for one segment is 20mA. I have no desire to overdrive the ...
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0answers
71 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 ...
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1answer
43 views

I'm getting a noisey/square wave output for my mux/demux?

I am using a "CD74HC4051 High-speed cmos logic analog multiplexer/demultiplexer" I put 5V to VCC, put my oscilloscope probe to the common out/in, put 3.3V to A1 (channel in/out), and have a wire ...
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81 views

How could I go about building a 2-bit comparator that compares two 2-bit numbers and determines whether one is greater than or equal to the other?

Using an 8:1 multiplexer, I understand there are three inputs, so I'm not sure how I'd go about getting two 2-bit numbers, which would be four variables, not three. Any pointers on how to get started ...
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543 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 ...
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65 views

Design a full adder of two 1-bit numbers using multiplexers 4/1

How can i implement the full adder of two 1-bit numbers using only multiplexers 4/1? I created a truth table for a one-bit full adder, which looks like this: A = first bit B = second bit Pu = bit ...
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2answers
305 views

Using Arduino Mega With lots of strain gauges

I was looking for a strain gauge shield for an Arduino Mega. I found this link which I found really useful: http://www.osengr.org/Projects/Load-Cell-Shield/Load-Cell-Shield.html At the bottom of the ...
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2answers
77 views

do demultiplexers remember

I'm working on a high school project were i need to make a score board using 420 LEDs controlled by an Arduino. I can see that the 74HC4105 demultiplexer will let us turn three pins into 8, but if we ...
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4answers
118 views

Easiest way to read a large bank of LED's

I have a pretty straight forward question but every answer I come up with seems over complicated or just plain wrong. I'm designing a data logger/fault detection system to be used for a large piece ...
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3answers
58 views

Is a multiplexed signal same as a composite signal?

Used to StackOverflow, this is my first question here. So please bear with me if the question is too simple and obvious to you as I am not good in Electrical Engineering stuff. I really need to ...
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2answers
89 views

Laser Multiplexing

I'm new to ECE stuff, but I was wondering what kind of equipment I'd need to have an 8x8 or more grid of lasers being controlled with specific on/off patterns. I'd want 5mW lasers in an 8x8 grid. It ...
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121 views

How to measure trace impedance?

I have seen that trace impedances in PCB's are maintained 50 ohm & so on. How to measure this impedance using a simple multimeter?
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97 views

Looking for a way to output 100-144 Analog Channels from Arduino

I've been searching for days and found 2 ways that could work, but not sure about implementation: Using shift registers like in: ...
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4answers
227 views

How to implement 8-bit 2:1 multiplexers on a PCB?

I need to implement a 2:1 multiplexer for 8-bit data. That is: as inputs it should take two 8-bit numbers and a Select line; and as output an 8-bit number. I could use two 74HC(T)157s (this is a quad ...
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1answer
70 views

Mutually exclusive headphone and speaker

I have a device that has only one set of analog audio out signals that are amplified for headphone usage. I want to be able to use these signals to output to a set of speakers OR a headphone jack, but ...
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1answer
181 views

A circuit having 2 inputs and 2 outputs

I am going to design a circuit that should have 2 inputs and 2 outputs. when both inputs are low both outputs should be low when input 1 is high and input 2 is low, output 1 should be a square wave ...
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3answers
207 views

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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3answers
49 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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2answers
328 views

Determine the Number of Transistors Needed to Build CMOS circuit

I would like to determine the number of transistors that will be used in the CMOS circuit below. Is there a specific formula for it?
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46 views

Multiplexing buttons using shift register - high impedance output

I have experience with 74HC4094, and I believe the 74HC595 is essentially the same - the datasheet says they have "tristate output", but that is only when OE is low - then all pins are tristate. What ...
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162 views

How do I find the Truth Table for Mealy State Machine?

This is a followup to my previous question: I have this assignment in college: You are to design a Mealy state diagram for a safety device. Assume that two debounced push-buttons, A and B, are ...
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89 views

Mealy Safety Device with 2 inputs

I have an assignment in college and I would like to ask some questions: You are to design a Mealy state diagram for a safety device. Assume that two debounced push-buttons, A and B, are available ...
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3answers
106 views

How to adjust red brightness on MAX7219 with RGB LED

I want to use MAX7219 (datasheet) to control bunch of RGB LEDs. With common anode LEDs I should be able to use up to 16 3-color bulbs in following configuration: simulate this circuit – ...
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1answer
100 views

Mealy machine to detect sequence of 2 inputs

I have the following assignment for a project at college and I have a few questions regarding it. You are to design a Mealy state diagram for a digital lock. Assume that two debounced push-buttons, A ...
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59 views

pin connection added

I am trying to communicate 24 hall sensor via arduino & 8:1 Mux . I am using CD74HCt4051E 8:1 multiplexer. Instead of hall sensor i have used potentiometer 24 nos and connected to MUX IC devide ...
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334 views

Audio Signal Switching - “DPDT switch vs. 4066”

I've got a signal coming from an electric guitar and I need to switch it. Basically it's a distortion circuit. I need to switch between the distortion and clean (directly connected to the output) My ...
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63 views

PIN selecting problem over arduino

My schematic as below. I have connected 8 hall sensor as shown in picture. Problem i am facing here is SO, s1, s2 The Led light are not glowing .Even the forard voltage across is 3.9v. i have tested ...
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1answer
100 views

Implementing F using a demultiplexer and an extra AND gate

Use a 1-to-8 Demultiplexer and an extra AND gate to create the function: F(x,y,z) = ∑m(1,3,5) If I were using an OR gate I think this would be trivial, simply put the 1 3 and 5 ...
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1answer
102 views

Multiplexer CD4067 bug:signal appears in unselected channels

I connected a multiplexer CD4067 with arduino. I will select ch0-ch15 in turn and pass the selected channel to A0 on arduino to do AD Convert. Then I only connected ch0 to 5V on arduino and selected ...
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105 views

High-voltage seven segment LED display driver problem

I've a circuit similar to THIS project, with a 74LS04 as inverters instead of 74HC54 (tested 74HC04 and CD40106 too) and ULN2003 instead of ULN2803. The circuit seems to work perfectly but when I turn ...
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185 views

Multiplexing problem with Arduino, MAX7219 e BJT

I tested the circuit below with an Arduino UNO, a MAX7219 and BC338. The sketch in Arduino is a chaser, so the leds should turn on in sequence. It consist of 7 segment (A-G) and two Digit (0-1). The ...
2
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1answer
65 views

A circuit that outputs one input voltage by default, or another if it is present

I'm trying to come up with a simple design that will take two analog inputs voltages (~0.2-1.6 V each). One is an "internal" voltage and should always be present. The second "external" input can be ...
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1answer
197 views

i2C multiplexer to use multiple sensor of the same type

I would like to hook up multiple sensor of the same type (temperature, pressure and so on). The problem is that each sensor can only have 2 different unique values for the register, so can't put more ...
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How does one implement the following function with these tools provided?

Suppose I have a function defined as follows, such that it is expressed in POS form, with the product of the following max terms of 4 variables (A,B,C,D): 0,3,4,7,9,10,12,15 and I only have a 4 to 1 ...
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72 views

Can avrdude address individual usbtiny programmers?

I'm envisioning a panel programming jig. In my mind, it consists of a Raspberry Pi, a powered USB hub, and a collection of usbtiny clones each connected to a pogo jig and a target on a panel. The ...
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265 views

Custom built 16x32 (40) LED Matrix controlled by Arduino

I am planning to build a clock / thermometer / info display. I have ordered 10 pieces of 8x8 LED matrixes from ebay (http://www.ebay.co.uk/itm/331064583297). As this is not a pre-built one I have got ...
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MAR /MBR / MUX Device

How can I modify this circuit to permit loading of the MBR from either the hex keyboard or from memory. As it is, the circuit can only load the MBR from user input.