- #1
chrisalviola
- 80
- 0
is it possible to connect 2x 7447 IC's and 2x 7 segment and input binary 0-15?
Click For Summary
Discussion Overview
The discussion revolves around the feasibility of using two 74LS47 (7447) integrated circuits (ICs) to input binary numbers ranging from 0 to 15 and display the corresponding decimal values on two 7-segment displays. Participants explore various approaches, challenges, and alternatives related to this implementation.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
- Mathematical reasoning
Main Points Raised
- Some participants suggest that using two 7447 ICs could work, but one participant notes that the 7447 can only display numbers up to 9 correctly, leading to potential issues with higher values.
- One participant proposes using a Fairchild 9368 chip instead of the 7447, as it can decode binary inputs of 10 to 15 correctly, thus simplifying the design.
- Another participant emphasizes the limitations of the 7447, stating that the output for numbers greater than 9 would be incorrect and suggesting that alternative ICs would be more suitable.
- Some participants discuss the possibility of using 7490 counters to drive the 7447, allowing for counting up to 99, which could be part of a larger project like a frequency counter.
- There are mentions of using AND gates and other ICs like the 4026 for better integration with 7-segment displays.
- One participant inquires whether this is a school assignment, while another clarifies that the project is intended for a count-up timer application.
Areas of Agreement / Disagreement
Participants express differing opinions on the suitability of the 7447 for this application, with some advocating for its use while others strongly recommend alternative ICs. The discussion remains unresolved regarding the best approach to achieve the desired functionality.
Contextual Notes
Participants highlight limitations related to the 7447's output for numbers greater than 9 and the potential need for additional components or alternative ICs to achieve the desired results.
- #2
waht
- 1,502
- 4
yes, that would be a fun project.
one chip takes 9 as the highest number, so you would have to do some splicing and gating.
but it's sort of redundant to use the second chip, 1 could be displayed with just one control line.
one chip takes 9 as the highest number, so you would have to do some splicing and gating.
but it's sort of redundant to use the second chip, 1 could be displayed with just one control line.
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- #3
chrisalviola
- 80
- 0
can give me a schematics on this or maybe a link so i can implement this
- #4
Bob S
- 4,662
- 8
Hi Chris-chrisalviola said:
Do you want to input binary 1111 and get output octal 17, or decimal 15 ?
Bob S
- #5
vk6kro
Science Advisor
- 4,079
- 41
The 7447 is a poor choice for this.
Instead of using several chips to compensate for using the wrong decoder, you could look for a device like the Fairchild 9368 chip which decodes binary inputs of 10 to 15 as A, b, C, d, E and F which are the correct HEX outputs for these inputs.
So, you would only need one of them and one 7 segment display.
Instead of using several chips to compensate for using the wrong decoder, you could look for a device like the Fairchild 9368 chip which decodes binary inputs of 10 to 15 as A, b, C, d, E and F which are the correct HEX outputs for these inputs.
So, you would only need one of them and one 7 segment display.
- #6
chrisalviola
- 80
- 0
@vk6kro
the decoder i have now is only 7447 ic so i have to make use of this.
@Bob S
in 1 of the 7447 ic you need to input 0000 upto 1111(15) so it should display the decimal equivalent in the 2x 7 segment. if its 15 the 1st 7 segment should display 1 and the other 5.
this is what the cuircuit should look like.
the decoder i have now is only 7447 ic so i have to make use of this.
@Bob S
in 1 of the 7447 ic you need to input 0000 upto 1111(15) so it should display the decimal equivalent in the 2x 7 segment. if its 15 the 1st 7 segment should display 1 and the other 5.
this is what the cuircuit should look like.
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- #7
vk6kro
Science Advisor
- 4,079
- 41
@vk6kro
the decoder i have now is only 7447 ic so i have to make use of this.
If you can't make use of any other ICs, then I don't think you can do that.
The second digit would always be a 1 or a 0, but the 7447 output on the right hand digit would be garbage for numbers greater than 9. It makes a series of letter "C"s oriented in different directions.
If you can make use of any other IC's you should throw out the 7447s and use a suitable chip. These chips are very cheap.
It is a simple job with a microprocessor and cost effective as well. You could have 8 bit binary pretty easily decoded to 3 displays.
Is this a school assignment?
the decoder i have now is only 7447 ic so i have to make use of this.
If you can't make use of any other ICs, then I don't think you can do that.
The second digit would always be a 1 or a 0, but the 7447 output on the right hand digit would be garbage for numbers greater than 9. It makes a series of letter "C"s oriented in different directions.
If you can make use of any other IC's you should throw out the 7447s and use a suitable chip. These chips are very cheap.
It is a simple job with a microprocessor and cost effective as well. You could have 8 bit binary pretty easily decoded to 3 displays.
Is this a school assignment?
- #8
chrisalviola
- 80
- 0
vk6kro said:
not at all, i was thinking of using this 4 binary input as a count-up timer given the input was from a 555 ic and a 7490.
- #9
vk6kro
Science Advisor
- 4,079
- 41
So, just use two 7490's. They only give BCD out anyway, but you can have one driving the next. Each 7490 can drive a 7447 which can then drive a 7 segment display.
This would let you count up to 99 before it starts again.
You would then have the beginnings of a frequency counter.
This would let you count up to 99 before it starts again.
You would then have the beginnings of a frequency counter.
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- #10
AskTheGenius
- 10
- 0
You should put an AND gate on the counter with the inputs on QA and QD and the output connected to the reset of the counter
or instead you can use a 4026 ic that has the outputs decoded for a 7- segment lcd display.
if you are connecting them together then connect pin 5 of the first 4026 to pin 1 of the other
second of all, you need to give a clock pulse to pin 1 of the first countergoogle: "integrated circuits by generic number"
and click the first link. it has datasheets for every ic (except for a few)
or instead you can use a 4026 ic that has the outputs decoded for a 7- segment lcd display.
if you are connecting them together then connect pin 5 of the first 4026 to pin 1 of the other
second of all, you need to give a clock pulse to pin 1 of the first countergoogle: "integrated circuits by generic number"
and click the first link. it has datasheets for every ic (except for a few)
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