Questions tagged [7segmentdisplay]

A numeric display consisting of seven segments per digit, allowing characters 0 to 9 to be displayed by selecting which segment is on or off. Can have each digit independently controlled, or can be multiplexed to reduce pin count. An 8th segment can be included for a decimal point.

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2 answers
136 views

NPN transistor not emitting anticipated voltage [closed]

I have 12 V connected to the collector of an NPN transistor. I have a pin of an ESP8255 (which emits 3.3 V) connected to the base. I'm trying to power a 7-segment display with it, but the emitter ...
2 votes
1 answer
247 views

7 segment display dimmed when off

I have a 7 segment display with a common anode which takes around 12 V. There's a 330 Ω resistor connecting each data pin to an ESP8266. To display each number, I'm just tying the requisite pins low. ...
3 votes
2 answers
284 views

What is the correct way to connect resistors to a common-anode seven-segment display with a microcontroller?

What is the correct way to connect resistors to a seven-segment common-anode display with a microcontroller? Where should I connect a resistor? Here I am connecting a common anode display (common = +5 ...
1 vote
1 answer
122 views

Why is my 7-segment display not working when output modules (O3-O0) are connected to BCD to HEX converter module?

I have used an 8051 interfaced with an 8255 taking inputs from port A and port 1 and showing the output from port B AND C of the 8255. I also made a decoder for BCD to HEX (0-F). The input value is ...
2 votes
3 answers
74 views

What are the considerations of using a common anode 7-segment display over a common cathode?

Common anode: Do I need resistors here? Where would I connect them? Common cathode: Common anode seems simpler circuit wise - but I like the idea that "1" represents "ON" that ...
0 votes
0 answers
34 views

Connecting a 7-segment display to a CD4543B decoder

I would like some help connecting a 7-segment display to a CD4543B decoder according to the instructions in the image at the bottom, and get the display to show the expected numbers. How is it ...
1 vote
1 answer
84 views

Why does the up down counter with 7-segment simulation always show X output? [closed]

Why does the counter output remain unknown (x)? I expect the counter to increment. ...
2 votes
4 answers
375 views

0 to 999 Hz frequency counter

I'm trying to build a frequency counter with a resolution of 1 Hz that will count any frequency between 0 and 999 Hz and hold that value. I've built the following in Multisim but I'm having trouble ...
1 vote
2 answers
183 views

D flip-flop circuit to show nine hex numbers alternately on one seven-segment display

I tried to make a circuit with a D flip-flop to show a hex number of F1D021301 alternately on a single seven-segment display, but it can only do F1D02130 or F1D0213 and return back to 0 and repeat to ...
0 votes
0 answers
58 views

7 Segment display loops back to 9

I am trying to figure out why the 7-segment display at the top part loops back to 9 when the timer reaches 0. I want the timer to display 0 whenever it stops. What kind of adjustments should I make to ...
1 vote
2 answers
97 views

Is BCD to 7 segment display a decoder or a driver?

In my book it specifically says that for decoders only one output is high for combinations of each input. And also the number of outputs are 2 power of number of inputs. None of these are true for BCD ...
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1 answer
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How do I connect a D flip-flop to a common anode 7-segment display?

I have a circuit in which I have an SN74LS175N D flip-flop, which outputs Q and Q’, and an INND-TS40Y6AB common anode 7-segment display. My goal is to make it so that when Q is true, only the “a” line ...
2 votes
1 answer
46 views

Reset of TM1638 display driver

I am trying to run a TM1638 display off the 6-pin program header of an ATMEGA328P that uses pins PB3, PB4, and PB5. The screen works fine, but the programmer works only if the screen is not connected. ...
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1 answer
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Unable to display entered digits via KEYPAD-PHONE in Proteus correctly

I've started doing some project that includes displaying entered digits via keypad phone in Proteus. I'll leave a screenshot below, so this post doesn't look undefined. You've probably seen this ...
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0 answers
44 views

Activating an Active Buzzer from PWM Signal of an LED driver

I would like to turn on an active buzzer TMB12A05 using the decimal place output channel of a TM1638 display driver that is designed to drive LEDs using a PWM signal. I considered using a passive ...
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-2 votes
2 answers
204 views

How do seven segment displays show black numbers?

Usually, seven-segment displays emit red coloured light, which is understandable. But in digital watches, the common colour used for the numbers displayed is black. But black light itself can't be ...
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2 votes
2 answers
424 views

How do you cascade two 7-segment decoder ICs together?

We used one 74LS47 IC in our lab, which we connected to a 7-segment display and tested the outputs. Now our instructor has told us to cascade two 7447 ICs together and implement it on a 7-segment ...
2 votes
0 answers
155 views

Reading 2 digit 7 segments with ESP32 using TM1650 maybe?

I have been trying to contact a forum member that has done a modification to his pool equipment in order to control it remotely instead of having to go to the box every time and check on the codes. ...
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7-segment display decoder truth table

I am trying to make a decoder that can display all alphabetical letters on a 7-segment display. My inputs are ABCDE and the outputs are abcdefg Is this the correct truth table for a circuit? If yes, ...
1 vote
1 answer
107 views

How to drive 1 x 168 LCD using 4 x 32 LCD driver?

I have to drive an LCD that has only single COM and 166 segments: Somehow using 4 x 32 LCD driver: So I am going to use five such LCD drivers (32+32+32+32+32+32) ...
0 votes
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90 views

Intercepting 7 segment display control on a proprietary PCB with unknown IC

So I'm trying to intercept the control of the 7-segment display on body weight scale to display huuuge negative numbers on remote control (to prank my friend). I've cracked the scale open and ...
0 votes
1 answer
145 views

DIY Multiplexing circuit to drive 7-Segment displays like they did in the 1970's

My old CMOS cook-book shows a generic block diagram for a MUX circuit to drive many 7-segment LEDs. It's assumed the reader will use an off-the-shelf MUX chip to drive the displays, but I don't want ...
0 votes
1 answer
71 views

Does a demultiplexer affects as a PWM would do?

I'm designing a circuit which has to display 8 numbers. I pretend to do it with 7-segments displays. I dont have enough pins in my MCU to control every single display independently, thus, I will use a ...
4 votes
3 answers
184 views

Help troubleshooting an unstable 595 shift register

Summary I am looking for help troubleshooting a couple of shift registers that seem to be unstable in a digital wall clock that I've built back when I was active in this stack, back in 2014. More than ...
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1 answer
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Design using 5x1 Mux, would this have any complications?

I am building a stopwatch with 5 counters. All are BCD counters with the exception of 1 modulo-6 counter (10ths, 1s, 10s, 1mins, 10mis.) I intend to pass these to the 7 segment displays on my board. ...
0 votes
1 answer
100 views

Help with AVR ADC and Serial port programming and integrating with python

I am a 2nd year electrical engineering student. I was stuck at this: Why do both seven segment displays show only 8 even when simulation is not running? Basically I am trying to take temperature data ...
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2 answers
194 views

Controlling brightness on multi-digit 7-segment display

I'm designing a velocimeter and I'm having doubts about the display's brightness control. I have an ATTiny 2313 microcontroller connected to a CD4511 that drives a common-cathode 3-digit 7-segment ...
0 votes
1 answer
110 views

Four digit 7 segment ghosting issue

I am facing an issue while driving a four digit 7 segment display using a TI MSP430 MCU. Some digits are overlapped. Below is the code we are using: ...
0 votes
1 answer
194 views

How do I wire a seven segment LED display to display binary input from two buttons?

I've been tasked with implementing a circuit involving a seven segment LED display and two switches/buttons. One will inject '1' and the other injects '0' into the circuit, and every four inputs a ...
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1 answer
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Question about 7 segment 4 digit led custom board

I have problem that is driving me nuts and I am hoping another pair of eyes can help me see the light. I have made a custom board using the esp32 as a micro controller. On that board i have breakout ...
0 votes
1 answer
93 views

How can I make a 7-segment display driver immune to intermediary states using basic logic gates (where each gate has a 1hz refresh rate)?

How can I make a hexadecimal 7-segment display driver immune to intermediary states using basic logic gates (where each gate has a 1hz refresh rate)? The problem I'm running into is that on the first ...
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2 votes
2 answers
73 views

7 segment LED displays

I notice the surface area of the decimal point in my 7 segment displays is only 1/4 of the ABCDEFG segments. Should I reduce the drive current accordingly, to achieve matched brightness? Can't find ...
0 votes
1 answer
148 views

Arduino - Inverting Common-Anode 7 Segment Display with a Transistor

I am currently struggling a lot with a tedious issue - I have to control my 7-segment display with a CD4511 decoder. However, my display is Common Anode, and it is not changable in my case. The best I ...
2 votes
1 answer
339 views

7 segment display input inverted

I was going through the tutorial in https://www.101computing.net/bbc-microbit-counter-using-a-7-segment-display/ using a 7-segment display I got from an electronics shop about 10 years ago. ...
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1 vote
1 answer
313 views

Implementing two seven-segment displays to display 2-digit numbers (0-30)

Without using an Arduino and microcontrollers, is this the most efficient way to implement two seven-segment displays to show 2-digit numbers (0-30) with the help of BCD decoders? $$ d_1=d_2=0\\d_3=AC\...
5 votes
6 answers
439 views

Is there a way to control a 4 digit 7-segment display without a shift register?

I am trying to run a 4-digit 7-segment display using a RPi as a microcontroller (and there is a reason this is here and not on the RPi stack). However, all the tutorials i found require a 74HC595 ...
1 vote
1 answer
253 views

Can I drive a common anode multiplex display with MAX7219?

I am trying to integrate with a pre-existing common-anode 3 digit, 7 segment LED panel (spoiler, it's a jukebox wallbox custom conversion) using a MAX7219, which will be controlled by a Raspberry Pi. ...
0 votes
2 answers
224 views

How to show excess-3 on a seven segment

I want to make an excess-3 adder and an excess-3 subtractor using two 4-bit binary adder (the inputs are already in exess-3) and then show the results in excess-3 on a seven segment. for example, 2+7=...
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-1 votes
2 answers
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7segment driver with PIC microcontroller

I'm trying to drive a 7segment using PIC microcontroller. This is the circuit diagram: In the picture, PIC means some ports of the PIC microcontroller. I want to pass 3 mA through each LED, and since ...
0 votes
1 answer
479 views

Problem of displaying addition and subtraction in decimal form on 2 Digits 7 segments in Proteus

I want to close a addition and subtraction circuit inside the Proteus program And display the sum and subtraction result in decimal on 7 parts I put the circuit image The problem with my circuit is ...
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0 votes
1 answer
106 views

Determining pinout on this Seven Segment Display

I have a seven segment display with 14 pins on each side and three digits. The display include a decimal point. However, I'm struggling to figure out the function of each pin. This item is ...
-1 votes
2 answers
103 views

Measure and display power consumption of DC motor

My daughter wants to be able to measure the power being used by a small motor under different loads as part of an A-level engineering project. Ideally this would be displayed in 7-segment display(s). ...
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1 answer
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Is it safe to fix a segment LCD on a panel with hot glue?

I'm talking about an LCD like what is shown in the picture below. Can hot glue applied to its borders damage the liquid crystal molecules or anything else inside it? I searched on the web and found ...
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-1 votes
2 answers
190 views

Am I crazy or has my collegue made a mistake?

I am reviewing a prototype design that someone else made. In the design, they use this part. See image. There are made holes in the PCB for the green marked plastic pins but only exposed surface ...
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4 votes
3 answers
602 views

Using 1N4148 diodes on segments of multiplexed 7-segment LED display

I'm a self-taught/hobbyist electronic engineer, and I enjoy taking apart old scrap electronics both to salvage components and to try to study design patterns (and as a challenge!). I've recently ...
0 votes
1 answer
272 views

7 segment display not showing digits simultaneously with an ATMega32

I want to show the digits'18221021' simultaneously. The seven segment display should show all 8 digits at a once. I wrote the following code. It shows all the digits but not simultaneously. It is ...
0 votes
1 answer
237 views

How do I connect to a 74LS47 decoder in ORCAD capture cis?

As the question says, I have been trying to connect inputs to a 7447 (7-segment decoder) but I get unknown segments in the pspice simulation, I am using capture CIS and I cannot figure out how to ...
0 votes
2 answers
62 views

Can I use any brand led digital display (18 pin) to replace a part for a control board in a washing machine?

I am replacing a control board in a washing machine. The replacement parts do not have the led 2 digit display part attached. Can I use any brand of digital display as long as the pins match up. The ...
0 votes
1 answer
288 views

3 Bit Counter w/ 7 Segment Display Starts at 111 instead of 000

The goal for this task is to have a 7 segment display output my last name the first two initials of my first name. The output should be FURMANHE with F being the 000 state and 111 being the E state. ...
1 vote
1 answer
91 views

BCD 7447 powered by 7805 drops voltage

I am trying to use a BCD converter 7447 to display numbers on a seven segment display. Even before I apply any inputs or outputs, I observe that the VCC voltage of the 7447 drops (which is powered by ...

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