Questions tagged [multiplexer]

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

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2answers
203 views

What's the ideal positioning for analog MUX in microcontroller circuit? (in a design with two boards)

I'm designing a set of PCBS for a midi controller and am wondering what is the best placement for the multiplexers in my design. Here are the details: Board 1: a microcontroller (Teensy 4.0), power ...
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1answer
48 views

Combining 2x1 mux and 4x1 mux with AND gate [closed]

I've found an example from my teacher's notes and I've no clue how to solve it. Could someone help me? Find the F output Please go easy on me I'm still trying to learn this. My first attempt was ...
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2answers
30 views

CD4052 multiplexer with different input voltages

I've been working on designing a PCB for my indoor garden and i'm facing a problem i dont understand. In my design i use a multiplexer (cd4052), to choose which sense resistor my current sensing chip (...
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9 views

Keysight 34980A DAQ with 2 x 34922A Mux Modules

I am using Keysight 34980A Data Acquisition System with 34922A Multiplexer Modules. I read that there is availability of Internal Analog Buses from the connector at the rear of the mainframe with ...
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1answer
36 views

Confusion with serial controlled mux devices

I have 8 channels each with 3 possible unique inputs, see diagram below. I would like to be able to select which input each output connects to. The inputs are signals from ranging from a simple step ...
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2answers
51 views

Implement boolean function as multiplexer

Implement and as a multiplexer: How is that working? When I repeat from before: Y | out 0 | 0 1 | X So, this means, when ...
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1answer
43 views

Grounding one port of SPDT analog switch

We are using a micro-controller to interface RGB matrix (HUB75 connector). Matrix row can be selected using signal pins (A-E). Some RGB matrix suppliers require to use (CLK/DIN/OE) on (A/B/C) pins to ...
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1answer
69 views

How to multiplex 8 pieces of 74141 without transistors? [closed]

I'd like to use 8 pieces of 74141 in order to drive the same amount of Nixies with an Arduino. What approaches will I need to consider? Update: I'm able to drive 1 single Nixie with a 74141. The ...
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1answer
45 views

Multiplexing a 74141 Nixie driver with a MAX7219

I'm building my first Nixie project where 8 tubes need to be driven with an Arduino (I've managed to drive 1 single tube). I found out this can be possible with multiplexing. My question is, is ...
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1answer
94 views

32 bit multiplication using 16 bit?

Please Note by multiply I don't mean 11 * 11 = 11 But I mean 3*3=9 which is 1001 in binary I am interested in knowing the following about multiplying numbers: Let's say I have two 32-bit numbers like ...
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14 views

How can I construct 2:4 Decoder circuit with the help of IC74139 (74xx139)

This is the Truth Table for IC74139 (74xx139) that 2:4 Decoder: I just know to construct 1:4 decoder only. And when I build my circuit, it cannot meet the accuracy of that truth table... Can you help ...
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32 views

Segments not totally off when multiplexing 7 segments display with CD4051BE

I'm trying to make a display with several 7 segment displays so I decided to use multiplexing to make it work. I use CD4051BE to do that. The circuit is as follow: Circuit of the multiplexing The ...
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59 views

2:1 MUX connected to a D Flip Flop

I have to describe the function of the circuit below which is a 2 to 1 multiplexer connected to a D Flip Flop and even though I understand their functions individually I cannot really understand what ...
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1answer
67 views

How to implement the following boolean function with a 8:1 mux?

The following boolean function is given $$ f = (\neg a \land b \land \neg c) \lor (a \land b \land \neg c) \lor (a \land b \land c)$$ which should be implemented with a 8:1 mux. Write down the truth ...
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1answer
41 views

Voltage Limitations of a header being used as a voltage selector

I have an application that takes a reference voltage. These voltages could be considered 'low voltage' as they range from 0 to 1000 V. Below is a reference schematic of what I'm trying to accomplish, ...
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59 views

8 bit barrel shifter using 2 x 1 MUX in VHDL

Is it possible to write a VHDL code to exactly follow this diagram? I have written some codes before using subcircuits to form a larger circuit (for example 8 bit comparator using 1 bit comparators) ...
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1answer
66 views

How can I control a “high” voltage charlieplexed LED array?

Context I want to design a system that allows me to control different LED arrays that I have, which can be either conventional multiplexed arrays (MP) or charlieplexed arrays (CP), by just plugging ...
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0answers
44 views

How to connect wires to multiple Pads?

Not sure if this is the right community - please tell me if it isn't. I have a connector (see image below) to contact pads of a sample and connected them to a multiplexer. I want to replicate it. ...
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0answers
30 views

MUX Circuit Design with MUX MPC506

I am designing a watchdog circuit to read a number of 15 signals (analog and digital), so I decided to use MPC506AU as shown in the picture. First of all, can I supply it with +5 volts and leaving the ...
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1answer
83 views

Designing lookup table(LUT) for half adder in FPGA

I want to implement half adder using FPGA. For this I need to design CLB, more specifically LUT for half adder. I know LUT gives only one output. But, for half adder we get two output. One for sum and ...
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1answer
54 views

Mux gets damaged the moment power is on. How do I know that cause of this? [closed]

I am currently using a mux, ADG1419, and i have had frequent mux failure the moment I turn on power; the power and the GND of the mux shorts after the mux gets damaged. My only assumption is that the ...
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1answer
35 views

MCP23S17 - do I have to use both Chip Select and Hardware Addressing?

I've used MCP23S17 before. 6 of it and I just used Chip Select. Hardware address pins all 0. https://ww1.microchip.com/downloads/en/DeviceDoc/20001952C.pdf In datasheet, hardware addressing can be ...
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1answer
117 views

Figuring out what is this IC

I have this chip on a breadboard that i want to buy, in order to populate PCBs with it. I searched and searched the internet with the text that it has on the upper part of it, but no matter how much i ...
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29 views

Multiplexing 3 phase motor driver signals to drive a BLDC motor bidirectionally

I have this unidirectional 3 phase motor driver powered by a 3S LiPo battery and want to make it be able to switch direction of the brushless motor connected to it within software. The way to reverse ...
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1answer
92 views

How to convert logic gates to multiplexer in a circuit?

In one of my previous questions, I wanted to know what integrated circuit I could use to replace my logic gates in the circuit below: The accepted answer helps me to redesign my circuit and replace ...
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4answers
109 views

Multiplexing AC voltages

I have three 24V AC lines (from a sprinkler controller) that I need to multiplex into two 12 DC lines. Here's the circuit I designed, with the AC inputs on the left, and the DC outputs on the right. ...
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1answer
2k views

Why doesn't this circuit work?

I want to implement this truth table (in Figure 1.1) into a circuit using an 8-1 multiplexer. I did the circuit schematic (in Figure 1.2) in Xilinx ISE Design Suite and it does work, but when I try to ...
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2answers
91 views

Transmitting digital signal long distances, without complex parts

I'm controlling several multiplexers from NI DO modules. The multiplexers channel select inputs, A0-A4, are 5v. The DO modules output 5v TTL. On the bench I have everything working exactly the way ...
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52 views

4 address lines for 1 bit input

I am currently trying to design a 16 nibble RAM on logisim, whereby it takes 4 data input lines. However, what I am having the most trouble with is converting the 4 address lines into a single input, ...
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1answer
86 views

Can a Multiplexer be used as a Demultiplexer

I'm trying to build a musical machine for myself. I've come to a situation where I want to control 8 LEDs using 3 selector pins on my 74151 IC. I've attached the circuit diagram below. Looks like I'll ...
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2answers
87 views

Connect 16 outputs to as few pins as possible on a microcontroller

I would like to control 48 outputs from a microcontroller, with individual access to each of them. But let's focus on 16 outputs. My initial solution involved a 1:16 demultiplexer and 16 (actually 8 ...
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4answers
3k views

How can I control 8 LEDs using only 5 pins of a microcontroller?

How can I control 8 LEDs using only 5 pins of a microcontroller without using any shift registers or I/O expanders? By "controlling" I mean turning an LED or a set of LEDs on or off, not ...
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1answer
55 views

Using a 4-1 multiplexer

I have a 4-1 multiplexer. I am trying to learn how to use it and I understand the logic well enough, but since I have never had any electronics training, my knowledge is somewhat limited and without ...
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0answers
57 views

Why are the inputs on my analog multiplexer tied to each other in pairs? (0+1,2+3,3+4…)

I'm currently wiring the signal of 16 potentiometers into a CD74HC4067 16 Channel Analog Multiplexer. The circuit is powered by the 3.3V signal on the Teensy 4. P0 (the first potentiometer) is wired ...
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1answer
148 views

RFID antenna multiplexer

I am working on a project where I need to use a single RFID reader to read tags from 4 different positions (6 cm apart). It is OK to only read one tag at a time, so I figured an RF-compliant ...
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2answers
68 views

Using a minimal number of muliplexers to create a 55:55 multiplexer from smaller multiplexers

The Problem I have an array of 110 digital pins and I need to route the pins with one-way channels through a series of multiplexers such that the following conditions will always be true: Each pin ...
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3answers
163 views

Is this D Flip Flop positive edge triggered or negative edge triggered?

It is an edge triggered D flip flop where X is input, Y is clock, Q is output. Is this D Flip Flop positive edge triggered or negative edge triggered? ADD (copied from a comment): Actually I am trying ...
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2answers
49 views

What is the max voltage 74HC4067 IC can withstand on output side when non of the channels are selected?

I have 74HC4067 (ESD 200 V) Vcc 3.3V Switching voltage 3.3V Input voltage 3.3V In my application when non of channels are selected, 16 output pins will have connection to 100V 9mA source one pin at a ...
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3answers
67 views

Best design practice for relying on IC input diode current clamping?

I have a question about what the "best design practice is" for using ICs with current clamping diodes. Take for example the following IC: CD74AC251M (datasheet : https://www.digikey.com/...
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0answers
44 views

Building a 2 bit comparator tips and tricks with truth table

Build a 2-bit comparator using either two 74151 8-to-1 MUXs or two 3 to 8 binary decoders. Additional gates such as AND, NAND, OR, NOR, inverters can be used. So I got this question while coming ...
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0answers
52 views

What's wrong with the wiring of my multiplexer?

My circuit is wired as shown above -but with the EN pin I've tried connecting to ground and to power. I don't think its a code problem because when I wire inputs in directly everything reads normal. I'...
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1answer
45 views

Choosing an input signal based on whether a driver signal is floating

I have three inputs: an analog microphone signal (M+), a push-to-talk (PTT) signal, and a ground (G). The PTT signal is connected to G when the button is depressed and M+ should be carried, and is ...
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0answers
35 views

How to calculate how much voice channels is being multiplexed

I would like to know how I could calculate from the bitstream which has a bitrate of 2,048 Mbps into how much voice channels is being used. I know that the syn has 32 bits and sign is 16 bits. Bitrate ...
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2answers
587 views

How to implement a three-input LUT if I have a lot of two-input LUTs?

I have gone through various sources... But I am not quite sure what it is. For example, I have three input variables: A, B and C. Now I have to use two 2-input LUTs such that their input lines are ...
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2answers
28 views

VIH of digital selection inputs for analog Mux when supplied with 4096mV - CD4051 IC

I will use CD4051BM96 part number, DATASHEET On page 7 is shown specs of VIH. It shows VIH of 3.5V for 5V supply (this 70% of VDD), VIH of 7V for 10V supply (70%) and VIH of 11V for 15V supply (73.3% ...
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4answers
235 views

Is this analog switch good for UART lines?

Currently designing a circuit to switch between two UART lines using an analog dpdt switch. Been searching for a while and found the BL1532. The datasheet says it's a DPDT USB2.0 Analog Switch, but ...
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1answer
65 views

In need for high variable capacitance

I am constructing a Chebishev or Butterworth audio filter (low and high pass), but I need to have all parameters highly adjustable - especially Fo and Q. For this purpose i would need to be able to ...
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1answer
50 views

Not getting correct results displayed from register

I am trying to input the numbers 1,0,3,2,32'hFFFFFFFF,32'h00000001 into the registers 0,1,2,3,6, and 7 respectively. I am doing this through always @(posedge clk) ...
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1answer
25 views

Raspberry Pi, SSR, Solenoid Valve Power (Multiplexing?)

Background I have a RaspberryPi-controlled irrigation sprinkler system that I am working on. I would like the RaspberryPi and the Solenoid Valve (when the Solid State Relay is closed) to pull power ...
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1answer
42 views

How to instantiate module with variables

I declared alu_result as a reg because I need it to be a variable data type for my case statement. But when i do this, I cannot pass it my ...

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