# Tagged Questions

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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### How do you convert a number to its 4-bit binary equivalent using logic gates?

Circuit storing number as binary ]2 My aim is to store numbers from 0-15(4 bits) as binary. The numbers are inputted using a keypad with buttons labelled N0-N9. The circuit works for single digit ...
55 views

### How to identify pinout of 7 segment display when data for it is not available online?

I found some 1-character 7-segment LED display in my toolbox with unusual pinouts. There is one however I can't seem to figure out and I even googled the part number with no results. The part number ...
5k views

### Why did my LED resistor burn while lighting four LEDs in series?

I have tried to create a circuit to switch a large 7-segment LED display (LDS-CD16RI) using a pair of MOSFETs, as follows: simulate this circuit – Schematic created using CircuitLab Here ...
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### Array of 4x7 Segment displays using demultiplexer. Need PNP transistors!

My first post here! I'm that most dangerous of EE-wannabes—a software guy with theoretical knowledge: V=IR, and transistors come in two flavours: "NPN" (1=On) and "...
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### I want to create a custom LED segment display. What do I need to study? [closed]

I want to create and then order a small run of a customized mass-produced LED segment displays for an art project. They will use PWM. It is not much more complex or detailed than a 7 or 16-segment ...
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### How to assign pins of Altera Cyclone II to 7 segment?

I am quite new to FPGA and I want to design a 1-digit counter on a 7-segment on an Altera development board. What I have done so far was to schematically design a bcd to 7-segment decoder in Quartus ...
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### how to determine resistor value calculation for common anode 7-segment display multiplexed

Resistor is required to limit the current flow through the LED since otherwise so much current will pass through that power dissipation shall destroy the LED in less than a second. For nonmultiplexed ...
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### Driving large common anode 7 seg LED with NPN transistor and arduino, worked but is it the right way?

I'm newbie, the circuit designed myself for driving large LED worked but I'm not sure is there better ways? I have only NPN transistors and common anode 7 segment display. Thank you.
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### How do I use the CD4026 IC with a multiplexed 7-segment display?

I have 2 pcs. of 3 digit multiplexed 7-seg display (ELT-511SURWA) and 6 pcs of CD3026. I am building a frequency counter (CD4060 + crystal as timebase). I have considered using 6x UDN2983 + CD4017 + ...
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### Display Double Digit Numbers on 2 seven segment displays

I'm making an Arithmetic Logic Unit(ALU) for an assignment and I'm on a point. So according to my circuit design on the link shared below, I am able to output 1 digit of my alu. It is a 4 bit ALU so ...
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### Why can a 74HC595 drive 8 LEDs?

I don't understand, I have seen many people use the 74HC595 to drive 5V across 8 5mm green LEDs via 220Ohm resistors at the same time, whereas the datasheet says that the maximum Vcc current is 70mA. ...
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### NPN or PNP for multiplex seven segment display?

I want to put three multiplexed seven segment displays on a pcb module which then will be connected to another board through a 1x12 Pin header housing an ATMega (so assume in the following that Pin 11 ...
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### LED radio display - How to control multiple segments at a time?

I have a display from an old radio (I think it was a Watson). Now, there are different wires connected to it: Let's call the first two A and B and one of the others (it seems to be not so important ...
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### converting an analogue signal to be viewed on a 7 segment display

How do I convert an analogue signal to a digital signal and display it on 7 segment LED's. This must be done without using any programmable micro-controllers. It's for a school project. The analogue ...
145 views

### Arduino based clock with 4 pieces 4" 7 Segment LED Displays [closed]

I was going through multiple tutorials on how to create an Arduino clock with 7 segment displays. I planned to build one and purchased 4 large (4 inches) 7 segment 1 digit displays. The displays run ...
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### Using 7-Segment Display on pic18f

I want to show a decimal number between 0-99 on 7-segment display by using 2 push buttons. These buttons will be used for incrementing and decrementing the number on display. I'm using pic18f assembly ...
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### MAX7221 experiencing 40C temperature rise above ambient

Each MAX7221 (2) in my current design is getting very hot. I used the FLIR One to get a general measurement. I observed a 40C rise above ambient. I'm not sure what the root cause is. Perhaps ...
76 views

### BCD to 7 Segment is producing too little voltage

I am trying to use a BCD to 7 segment decoder to power my 7 segment display. This is the decoder I'm using (http://www.mouser.com/ProductDetail/Texas-Instruments/SN74LS47N/?qs=...
159 views

### Increase voltage from 5 to 12V to deactivate a display

I'm developing a timer based on this project: Digital Stop Watch with ATmega8 by Avinash Gupta (I cant put the link, because my reputation is too low) Original schematic: At first, I made the same ...
107 views

### Can this shift-register circuit be simplified?

I've created a circuit using a shift register to drive a 7-segment display which is all controlled by an Arduino Uno. The circuit appears to work fine, I have a sketch running which simply counts ...
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### 0.56inch 7segment display failure

I am Nikhil from India, working as an embedded programmer. I made half inch 7segment display based digital clock. But after few months few 7segment displays got damaged. I got same complaints in many ...
68 views

### Using a PAL for a seven segment display

I know next to nothing about PAL. I was wondering how one goes about programming a PAL (an old TIBPAL 16L8-25CN in my case) to drive a seven segment display, sort of like a HEF4511B. Right now I just ...
105 views

### VHDL: How does one assign custom values to identifiers of an enumerated type?

For a design with seven segment displays, it will be easier in modelsim simulation if one can see the actual display value going into the seven segment display e.g hexadecimal D which is "1000010" in ...
99 views

### What is the pin to light up colon in Basys 2?

I am trying to make a clock in a Basys2 board but I can't find in documentation the pin to light up the colon of the 7segment display. Where is it?
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### Comparator and 7 segment display

I am trying to make a 7 segment display that displays the symbol <, > or = depending if a > b or a=b or a < b by using the output of a comparator(7 outputs from the comparator according to the ...
48 views

### Discrete Logic with Seven Segment Displays Problem

As a small project, I decided to make this circuit from Gadgetronix. However after wiring it, the display is stuck on 20 and when I activate the pushbutton, the 0 (display of IC2) just dims, and when ...
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### FSM 4x7 segment displays Verilog

I got problem getting around Verilog. I am trying to create a FSM that displays numbers on one of the displays and on the next state to display a string. I did make the string to be displayed ...
133 views

### How do digital watches use so little power (and how do I do that?) [duplicate]

The title of the question is pretty self-explanatory. I did a quick back-of-the-envelope calculation for my own digital calculator watch (the Casio CA-53W for those who are interested). The battery ...
71 views

### How would I create this kind of circuit?

I'm just starting out with electronics, this should explain why my "schematic" is so readable. I'll attach it and explain further. I know how to create a simple circuit with the main slide switch and ...
225 views

### Is the there an intended PCB layout for the MAX7219/MAX7221 I'm missing?

The ordering of the segment pins (14-17, 20-23) on the MAX7219/MAX7221 common-cathode LED display driver is unusual, to say the least: The order of these pins is similar, but not identical, to the ...
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### How to power a big high voltage 7-segment array with minimum parts, without frying my wimpy power supply?

I am trying to design a clock with a big 8-digit 7-segment display formed by about 250 LEDs, but with a power draw limit of 1A from a 5V USB phone charger. Each stroke is four LEDs in series and ...
368 views

### hexadecimal seven segment display verilog

I have a 4 bit output number as output. How can it be seen on seven segment display as hexadecimal number? I'm new and mentioning verilog. case example: ...
135 views

### How to “unground” a low state of a not gate

I have a seven segment display(LTS4680AE) and the anode of each segment keeps getting grounded. So I basically have a 4 bit adder which adds two 4 bit numbers and produces a 4 bit output. This output ...
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### Voltage to segments on 7 segment display?

I am thinking of purchasing an LTS4680 seven segment display for one of my projects.Here is the datasheetdatasheet:http://www.icpdf.com/icpdf_datasheet_7_datasheet/LTS4680AE_pdf_1732299/...
537 views

### How to display a double digit decimal value on a seven segment display?

I recently finished a 4 bit adder project and I wanted to "extend" it.Right now,the output is represented by 4 led's(1 for each bit).I want to display the answer as a decimal in a seven segment ...
135 views

### Designing logic for 7-segment display [closed]

I want to design the logic of a 7-segment display driver. As for the specs, I want it to have 4 inputs coding the binary value of numers 0-9 and 8 outputs for the display. I am not really sure where ...
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### 7 segment LED display not working when using common pin as cathode?

I am trying to wire up a 7 segment LED display but when I connect the common pin to ground and the LED pins to V+ the display doesn't work. However when I use the common pin as an anode and connect it ...
824 views

### 4 Digit 7 segment display LED missing one light (on all four digits) [closed]

Hi I ordered online a voltage meter and got this tiny cute little fast refreshing pretty darn precise reliable meter. HOWEVER I am missing on all four digits the left lower vertical light piece. What ...
103 views

### How can i connect 9 7segments to a 3x4 keypad using only diodes making each 7segment displays only one number? [closed]

I want to make each button in the keypad to display one number using only diodes without using any decoders or ic. thanks in advance
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### How to Separate 7 segment power supply

I'm trying to drive a multiplexing double digit 7 segment (5261AS) using Arduino and two shift registers (74595) I need to separate power supply for the 7 segment to avoid overloading current from the ...
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### How to control four 10-pin 7 segment display [duplicate]

I'm a student trying to make a device for our research project so I'm quite (if not entirely) new to electronics. I'm planning to make a 4 digit display using four 7seg display using arduino and each ...
208 views

### How to convert BCD to multi-digit 7-segment?

I have a BCD input in the form of 8 wires (eight bit number, up to 511 decimal) and I want to display it on a seven segment display. I have found a product which has 4 1/2 digits and a converter, but ...
159 views

### Problem with 7-segment display: dimly lit when off

I'm driving two large seven-segment displays using two shift registers (74HC595). The displays have a forward voltage of 12V and a max forward current of 20mA. I'm feeding data and 5V of power to the ...
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### Appropriate Brightness for LED Displays

This may be a question strongly depending on application and opinion, but I'll give it a try. I am designing some controls for an industrial application, including cap touch buttons and LED 7-segment ...
183 views

### Driving 2inch 7segment display using pic microcontroller

I want to drive 2 inch 7segment display(common anode) using pic microcontroller. The forward voltage of segment is around 7v. The emitter of the pnp transistor is connected to the12v power supply. ...
134 views

### Using a LS248 7-segment driver, but segments are dim. Can't figure out why

I'm building a project where I want to use two double-digit 7-segment-LED displays (green, common cathode). From what I've read, a shift register wouldn't be able to source enough current, so I ...
651 views

### Driving two large 7-segment displays using Arduino and shift registers

I recently started a project in which I want to control two 7-segment LED displays using two shift registers (74HC595) and my Arduino. I thought I had the basic ideas mastered, but I ran into some ...
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### 7 segment display orientation problem

So i am completely new on this topic. i have a problem which looks something like this. i have a light which is designed with a 7 segment display which gives the reading of various parameters . the ...