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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33 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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1answer
33 views

Logic in displaying numbers in 7 segment 4 digit display

what is the logic in displaying desired numbers in 7 segment 4 digit display. Ie, how to know the leg combinations to see the desired number in the display
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1answer
39 views

Additional current source for large LED-7-segment-display

I have two sets of LED-7-segs. Each with 4 Digits, all 4 inch tall. One set CC, the other CA. Combined they consume some smooth 1.68A / 1.4A according to the data sheets. That is manifold the ...
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0answers
36 views

Possible to copy a circuit from 1 Logisim .circ file into another Logisim .circ file?

I'm using Logisim to experiment with Electrical Circuit design, and I was wondering if it is possible to copy a circuit created in 1 Logisim .circ file and place it into a different Logisim .circ file ...
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0answers
17 views

Fractional Decimal to Base7 Conversion with Radix Points? [duplicate]

I was hoping someone on here could help explain Decimal to Base7 conversions with Radix points. I'm pursuing my Bachelors Degree in Computer Science with 12 courses remaining, currently in a Computer ...
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3answers
91 views

Decimal-Binary-Hex-Base7 Conversions with Radix Points?

I was hoping someone on here could help explain number base conversions with Radix points. I'm pursuing my Bachelors Degree in Computer Science with 12 courses remaining, currently in a Computer ...
0
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3answers
100 views

2 Digit 7 Segment Display Driver

I need to display the temperature acquired by my LM35 on a 2 digit 7 segment display. What I have is LTD383-R2 Common Anode Display. Datasheet here. The display has 1 Anode pin + 14 Cathode pins for ...
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4answers
280 views

Rotate a 7-segment display in firmware

I have a board with a 7-segment display controlled by an AVR. I need to rotate the display's characters in the firmware, so that the display is read correctly when physically rotated 180 degrees. ...
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1answer
56 views

Count number of hours elapsed

It's been a long while since I played with circuits, I'd appreciate a sanity check of the following design; I'm trying to count the number of hours since the reset button was last pressed. Ideally ...
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2answers
79 views

Using NPN Darlington to switch on PNP

I'm trying to separately switch on the digits of a 2 digit common anode 7 segment display (specifically the Lumex LDD-E2802RD because it's small and cheap). I think that the easiest way of getting my ...
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3answers
178 views

How to make 7-segment display count up ?

I've connect 7447 decoder and 74193 counter as shown in the picture but I have not used 555 timer yet. Is there any way to test the circuit before using 555 ? I've connected the pins (up and down) ...
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1answer
93 views

7 segment count jump from 00 to 05

I'm new at coding and need some answers, I doing some mini project and I got caught in some errors I'm not sure, I'm doing a ''photocopy'' machine and I have to code it in C under the Microchip MPLAB ...
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2answers
209 views

How to connect 7447 decoder to 7-segment display?

I've connected a 7447 decoder to 7-segment display as shown in figure. When I connect an input, the LEDs doesn't form numbers but they light up randomly. I just want to know the right way to ...
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4answers
77 views

Outputting a clock signal from an FPGA

Referring to question here: Click here, I'd like to use the 16 channel LED driver to run my 7-segment displays. I'm using a Spartan 6 LX9 FPGA to implement a 16-bit microprocessor that will take care ...
0
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1answer
127 views

Driving 7-Segment Displays using a microcontroller

Before I start out, let me just point out that I'm new to hardware design. In fact, this is just hobby for now, but might turn into something later. Because of this, I don't follow any standards per ...
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1answer
104 views

Simple high side driver for multiplexed 7-segment displays?

How can I best drive and switch high side power (for multiplexing) between the 7 displays with as few components as possible, for under $2. I am trying to simplify a design. I have a custom board ...
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2answers
100 views

Shift registers(?) failing after being left on a while

Resolved: SLCLR on SN74HC595 was not tied to VCC, so behavior was inconsistent. I have a custom built board that is running seven 7-segment displays, multiplexed using SPI from an 5v Arduino Pro ...
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2answers
199 views

Possible to use 7447 to drive common-cathode 7 segment display?

I know that the 74(LS)47 is designed to drive common-anode displays. However, is it possible to make it drive a common-cathode display? What is the simplest (in terms of components) way of doing this? ...
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2answers
181 views

How to drive a single 7 segment display with I2C?

I am looking for a solution to drive a single 7 segment display with I2C. I found some websites that shows 2 or 4 digits with I2C but I didn't find a solution for driving a single digit. I'm making a ...
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2answers
87 views

Difference between 7446,47 etc

I have looked in the data sheets, as well as the TI article, but I am still unsure of the answer to this question: What is the practical difference between a 7446 ("BCD to 7 segment decoder/driver ...
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1answer
99 views

7 Segment display binary to decimal

I have a few questions about 7-segment LED displays. When we build a circuit using 7 segment (common-anode) and decoder (7447), we also use 4 tactile switches to make combinations. Should I directly ...
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2answers
123 views

7-segment display driver IC [closed]

Which IC can I use to control 7-segment display? I want to make simple projects like a reaction timer but I don't have an Arduino or some other microcontroller available. What ICs can I use instead?
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1answer
98 views

How to read SAA1064 7-segment values

I have a central heating system that displays it's info and error codes on 4 7-segment displays. These displays are driven by a SAA1064, like so: This SAA1064 (datasheet here) receives it's ...
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1answer
100 views

Display for outside (sun)

I am currently working on a little project where I would like to have a display which would have to support this format: 00 00:00:00 This would have to be used outside on a motorcycle ...
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2answers
128 views

Driving three large 7.5v common anode 7-segment displays with Arduino

I'd like to drive three common anode 7.5v 10ma 7-segment displays using my arduino uno and a few 74HC595N shift registers. The problem is the uno only outputs 5v 40ma on the digital pins. I am ...
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2answers
84 views

low power displays

What kind of displays can I use effectively with a coin cell battery (CR2450)? The backlight or the entire display would be on only when necessary. From previous answers I know that a liquid crystal ...
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1answer
111 views

7-segment driving circuit not working as expected

I have designed and built the following 7-segment driving circuit utilising an Arduino Micro in order to try and further understand electronic circuit design: simulate this circuit – ...
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1answer
531 views

Display digits on 7 segment 3 digit LED display with Launchpad

I have a 7 segment led display with 3 digits (BT-M512RD-DR1 ) and Valueline Launchpad MSP-EXP430G2 I connected LED display according to this answer and here is my version of the sketch But I am ...
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0answers
104 views

Help with ICs, 2-digit 7-segment displays, 74HC4515

Can someone show me how to connect two DC56-11YWA 2-digit 7-segment LED displays to an Arduino Uno or Mega2560 using two 74HC4515s? Is there another IC that I will need in addition? I want to display ...
3
votes
2answers
173 views

How to “deserialize” a digital output to 4 digital outputs

I am working on a small test project for my Arduino and as part of it, I want to display a number on a 7-segment LED system. My first setup involved just direct links to the 7-segment display and ...
2
votes
2answers
165 views

BCD to 7 Segment Decoder Schematic: Need help fitting in page

I am working on the schematic for a BCD to 7 segment decoder right now. I understand the logic, but it is the design of the schematic that I need help with. Here is my schematic so far: As you can ...
2
votes
2answers
355 views

How to filter out the mains power supply spikes?

I'm purposely dropping AC from its normal levels (230VAC @50Hz) just to analyse the behaviour of a DC motor drive board that I have. When the AC mains voltage falls below 180V, the 7 segment display ...
2
votes
1answer
380 views

Constructing Excess 3 BCD to 7 segment decoder - circuit hints needed

I am currently trying to construct a circut for an Excess 3 BCD to 7 Segment decoder. Therefore the input range ranges from 0011 to 1100 in binary inclusive with the rest of the inputs being don't ...
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2answers
139 views

Reducing power consumption in controlling 40 7-segments [closed]

Following that post here: Designing a large 7-Segment display To give you the basic approach I did that: form the uC to shift register followed by ULN2003, then connected 8 7-segments together Put ...
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vote
3answers
144 views

Seven Segment problems,voltage and current

I want to ask a question about a project I am making, I am using a seven segment. Here is Information about the seven segment: http://www.4project.co.il/documents/doc_188_54.pdf I want to use this ...
2
votes
2answers
807 views

Weird ULN2003 to 7-segment behaviour in Proteus

I'm trying to drive a 7-segment common anode, in the following connection, however there is no output the comes from the ULN2003 at all, its like when it gets a 0 in the input, it gives a tri state ...
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1answer
274 views

Designing a large 7-Segment display

I'm trying to design a product that have the following features for mass production, and I'm asking from your experience, how to get the lowest price for the components, quality of the chips in terms ...
0
votes
1answer
152 views

How to connect 3-digit display and suppress leading zeroes?

I searched a little and it told me to use with more than one display, connect (Ripple Blanking Output) from most significant 7447 to the of the next 7447. Which number would be most significant? ...
0
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2answers
201 views

What seven segment display do I have? [closed]

I'm having a surprisingly hard time figuring out which seven segment display I have on a board I'm looking at. It is common anode, as there is one pin tied directly to Vcc. It's like this, except ...
3
votes
1answer
257 views

Why is my LCD stop to work correctly when my pump is running? [duplicate]

I have a 8x8x8 lcd/led/button module (tm1638 chip) connected to my Arduino r3. When I attach a pump (GPH350, 1.5A, 12V to the same power supply (12V, 5A) - my display stops working correctly (only ...
1
vote
0answers
315 views

MAX7219 interfaced with ATmega128 producing strange results on 7 segment display

I have built a circuit using an ATmega128 interfacing a MAX7219 decoder to control a 7-segment display. I would appreciate if anyone could help me figure out a problem I'm having with my setup. I am ...
2
votes
3answers
865 views

Cheap 4 digit 7 segment display driver

Can anyone recommend a cheap ( less than $4 ) driver chip capable of driving a 4 digit, 7 segment display with the center colon? I'm very familiar with the likes of the MAX7219 and similar but they ...
5
votes
1answer
78 views

7-Segment Decoder outputs/LED display

What would be the difference in using a 7-segment decoder with active-high outputs vs active-low outputs, to driver an LED display?
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votes
1answer
162 views

How to change colour of a 7-segment display using the Arduino [closed]

Is it possible to change colour of a 7-segment display using an Arduino Uno?
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0answers
341 views

Counters VHDL multiplexer 7 segment

I am new to vhdl and my code may seem stupid but i am still struggling i am trying to make a bcd counter using spartan 3 kit i have a problem multiplexing the 7 segment and i know i should use ...
3
votes
2answers
233 views

Shift Registers Controlling Seven-Segment Display without a Latch?

I'm restoring a Model H Skee-Ball machine, and these old models have a bunch of hardcoded settings and unreliable switch detection, so I want to replace the main control circuitry with something ...
0
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2answers
91 views

How to cycle through bits of information for a hex display?

I am doing some work with a Hex Seven Segment Digital Display with a built in decoder that takes in 4 bits of information. Controlling it I have 4 cascading T-FlipFlops whose outputs are inverted so I ...
10
votes
3answers
503 views

Low power, seven segment display

I want to display a 4 digit number on a small device that fits in a hand. I have a CR2032 3V battery at around 230mA, my microprocessor is a 8051 (in a BLE112) usually uses about 0.9µA and I want the ...
2
votes
1answer
290 views

How to use Darlington arrays to source current in a 7-segment display driver

I'm building a driver for a large common-cathode 7-segment display using a shift register and BJT transistors (more details in this question). I wanted to make it more compact by replacing the ...
1
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2answers
3k views

How to drive a 12V common cathode 7-segment display with 5V signals and BJT transistors?

I'm having trouble designing a driver for a large (5") 12V common cathode 7 segments display using a 74HC595 shift register and BJT transistors. Below are the schematics for the component (display) I ...