# Using 2x 74LS47 to input binary 0-15

• chrisalviola
In summary, it is possible to connect 2x 7447 IC's and 2x 7 segment displays to input binary 0-15. However, it would require some splicing and gating as the 7447 only takes 9 as the highest number. It would be more efficient to use a single Fairchild 9368 chip. Alternatively, you could use two 7490's and two 4026's to count up to 99 before resetting. A clock pulse would need to be given to the first counter and an AND gate could be used for a frequency counter. Datasheets for these IC's can be found by searching "integrated circuits by generic number" on Google.
chrisalviola
is it possible to connect 2x 7447 IC's and 2x 7 segment and input binary 0-15?

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.

Last edited:
can give me a schematics on this or maybe a link so i can implement this

chrisalviola said:
is it possible to connect 2x 7447 IC's and 2x 7 segment and input binary 0-15?
Hi Chris-
Do you want to input binary 1111 and get output octal 17, or decimal 15 ?
Bob S

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.

@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.

Last edited:
@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?

vk6kro said:
@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?

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.

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.

Last edited:
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)

#### Attachments

• 4026tab.gif
10.1 KB · Views: 1,116
Last edited:

## 1. How does using 2x 74LS47 help in inputting binary 0-15?

The 2x 74LS47 is a BCD-to-7-segment decoder/driver IC, which means it can convert binary-coded decimal (BCD) input into a 7-segment display output. By using two of these ICs, we can input binary numbers from 0-15 and display them on a 7-segment display.

## 2. What is the advantage of using 2x 74LS47 instead of a single IC?

Using two 74LS47 ICs allows us to input a wider range of binary numbers (0-15) compared to a single IC, which can only handle numbers from 0-9. This makes it more versatile and suitable for different applications.

## 3. Can the 2x 74LS47 be used for inputting binary numbers higher than 15?

No, the 2x 74LS47 is designed to work with binary numbers from 0-15. If you need to input higher numbers, you can use additional ICs or look for other alternatives that can handle a wider range of inputs.

## 4. How do I connect the 2x 74LS47 to the 7-segment display?

The 2x 74LS47 has four input pins (A, B, C, and D) that correspond to the four binary digits of the input. These pins should be connected to the corresponding pins on the 7-segment display. Additionally, the IC has seven output pins (a, b, c, d, e, f, g) that control the segments of the display. These pins should be connected to the corresponding segments of the display.

## 5. Are there any precautions to take when using the 2x 74LS47?

Yes, it is important to follow the manufacturer's datasheet and ensure that the IC is properly powered and grounded. It is also recommended to use a pull-up resistor on the input pins to prevent any floating inputs. Additionally, make sure that the input and output pins are connected correctly to avoid any malfunctioning.

• Beyond the Standard Models
Replies
14
Views
3K
• Engineering and Comp Sci Homework Help
Replies
1
Views
2K
• Engineering and Comp Sci Homework Help
Replies
5
Views
1K
• Engineering and Comp Sci Homework Help
Replies
1
Views
2K
• Engineering and Comp Sci Homework Help
Replies
11
Views
2K
• Electrical Engineering
Replies
7
Views
1K
• Engineering and Comp Sci Homework Help
Replies
12
Views
2K
• Engineering and Comp Sci Homework Help
Replies
3
Views
2K
• Engineering and Comp Sci Homework Help
Replies
4
Views
2K
• Engineering and Comp Sci Homework Help
Replies
5
Views
2K