How to conect 7447 in circuit board to make 7-seg desplay workin

In summary, the conversation is about making a wind speed indicator using a 7-segment display and 7447 chips to convert an 8-bit quantity from an ADC. The user is stuck on how to connect the two 7447 chips and is also unsure about how to convert the 8-bit quantity into a wind speed reading in kilometers per hour. They are seeking advice on how to approach this problem, and are considering using a microcontroller or discrete logic. They are also reminded to do their own research and not expect others to do the work for them.
  • #1
dubai boy
2
0
hello everybody i am glad to find this websit and hope its gona help i am student in my last year in betec deploma course and have to do my iva wot is my graduation project so i am willing to do wind speed indactor and i am stuck kn in converter to change the 8bits to 7-seg then to display screen ,,,


i got two 7447 wana conecte it to the circuit board bt do no how to make it work and give me the digit number?


is that all wot i need or its som staff missin to make it work?
 
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  • #2
I'm not sure I understand your question (it is not worded clearly), but I'll try to offer some help nevertheless.

You want to make a wind speed indicator with a single 7-segment display? You will display wind speed as 0-9kph? Or will you use two 7-segment displays to be able to display a wider range of speeds?

What are you using to sense wind speed? You say you get an 8-bit quantity -- how are you making that? 8 bits gives you a 0-255 number...what is the calibration to wind speed in kilometers per hour?

There are ICs that convert 4-bit binary numbers directly into the 7 segment drive lines -- do a little google searching to find those ICs. If you want to make your own instead, writre out the truth tables for each of the segments based on a 4-bit input number, and design the logic based on a Karnaugh map for each of the segment truth tables.
 
  • #3
berkeman said:
I'm not sure I understand your question (it is not worded clearly), but I'll try to offer some help nevertheless.

You want to make a wind speed indicator with a single 7-segment display? You will display wind speed as 0-9kph? Or will you use two 7-segment displays to be able to display a wider range of speeds?

What are you using to sense wind speed? You say you get an 8-bit quantity -- how are you making that? 8 bits gives you a 0-255 number...what is the calibration to wind speed in kilometers per hour?

There are ICs that convert 4-bit binary numbers directly into the 7 segment drive lines -- do a little google searching to find those ICs. If you want to make your own instead, writre out the truth tables for each of the segments based on a 4-bit input number, and design the logic based on a Karnaugh map for each of the segment truth tables.

sorry 4 my writing or nt make it clear i got a fan which is spining by wind conected to mini motor which is change to generator to prduosing voltage so the voltage gona go thrught the a/d convertor so the convertor gona give me the reading in 8bits i did some reasirch and find the 7447 gona change the 8bits to 7-seg deget then i can read it in display screan so far i am stuck in how can i conect the two 7447 chip in circuits board and i gona read the wind speed by k/h then i gona add m/s mile knots so if i miss somthin could are u ppl be kind enugh to aske and thanks aloot
 
  • #4
dubai boy said:
sorry 4 my writing or nt make it clear i got a fan which is spining by wind conected to mini motor which is change to generator to prduosing voltage so the voltage gona go thrught the a/d convertor so the convertor gona give me the reading in 8bits i did some reasirch and find the 7447 gona change the 8bits to 7-seg deget then i can read it in display screan so far i am stuck in how can i conect the two 7447 chip in circuits board and i gona read the wind speed by k/h then i gona add m/s mile knots so if i miss somthin could are u ppl be kind enugh to aske and thanks aloot

Okay, so it sounds like the initial problem is how to make a 2-digit 7-segment display from an 8-bit number. Well, since a 2-digit display can display 00-99 (assuming you don't do a HEX display), then you only need 7 bits from your ADC. The typical way would be to ignore the lsb of the 8-bit ADC output, and convert the upper 7 bits to the drive for the 7447 chips. The easiest and quickest way to do that, is to use a microcontroller (uC) to read the 7-bits of the ADC output and do the code conversion to form the 8 drive lines for the two 7447 chips. Alternately, you can do it in discrete logic, it will just take more work. You will need to write the truth tables for the two digits (the tens digit and the ones digit), and show how to convert from the 128 possible 7-bit codes to the 100 decimal codes for driving the displays. Be sure to pin the number at 99 for all readings over 99.

You can use google to get more information for your research. Google the following:

binary to decimal converter IC "2-digit"

and look around at some of the hits. Have fun!
 
  • #5
BTW, keep in mind that we do not do your work for you. So we will not post circuits and papers that will help you short-cut figuring this all out for yourself. The hits you will see from that search will help you with some background information, but there are no exact implementations of how to do it. That is up to you to figure out and build.
 

1. What is a 7447 and how does it work?

The 7447 is a type of BCD-to-Seven-Segment decoder/driver integrated circuit (IC) that is used to convert binary-coded decimal (BCD) signals into outputs that can drive a seven-segment display. It has four input pins for the BCD signals and seven output pins for the segments of the display. When a specific combination of BCD inputs is received, the corresponding segments of the display will be turned on.

2. How do I connect the 7447 to a circuit board?

The 7447 can be connected to a circuit board by soldering its pins to the appropriate locations on the board. The datasheet for the IC will have a diagram showing the pinout and recommended connections. It is important to follow the datasheet carefully to ensure proper functioning of the IC and display.

3. How do I connect the 7-segment display to the 7447?

The 7-segment display will have eight pins, with one being a common cathode or anode and the remaining seven being segment pins. The common pin should be connected to the appropriate output pin on the 7447, and the segment pins should be connected to the corresponding output pins on the IC. The datasheet for the 7-segment display will have a diagram showing the pinout and recommended connections.

4. What is the purpose of the 7447 in a circuit?

The purpose of the 7447 is to simplify the process of driving a seven-segment display by converting the BCD signals into outputs that can directly control each segment of the display. Without the 7447, more complex circuitry would be required to achieve the same result.

5. Can I use multiple 7447s to control multiple 7-segment displays?

Yes, multiple 7447s can be used to control multiple 7-segment displays in a circuit. Each 7447 can control one display, so the number of displays that can be controlled will depend on the number of available ICs and the available inputs on the circuit board. It is important to consider the power requirements and limitations of the circuit when using multiple 7447s in a design.

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