Circuit that takes a pulse from a 555 chip

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Discussion Overview

The discussion revolves around converting binary output from a 555 timer circuit through 7490 counters into a 7-segment LED display. Participants explore various methods and components for achieving this conversion, including the use of BCD and specific integrated circuits.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant describes a circuit that takes a pulse from a 555 chip and uses two 7490 switches to create a binary counter that counts up to ten, seeking help to convert this binary output to a 7-segment LED.
  • Another participant suggests using a specific seven-segment driver or setting up gates to create ten separate outputs to drive the display.
  • A participant mentions the need to convert binary to BCD and suggests using a 7447 for the conversion, noting that the 74185 chip is discontinued.
  • There is a query about setting up the 7490 for a carry-reset on A(hex), indicating a need for clarification on this setup.
  • Participants discuss the suitability of the 7446 versus the 7447 for the circuit, with some expressing uncertainty about which is preferable.
  • One participant raises a question about the counting range (0-9 or 1-10), leading to a light-hearted exchange about displaying "10" on a 7-segment display.
  • A participant mentions gaining access to a 4511 integrated circuit and seeks guidance on its use.

Areas of Agreement / Disagreement

Participants express differing opinions on the best components to use for the conversion, particularly regarding the 7446 and 7447 chips. There is no consensus on the optimal method for achieving the desired output, and several questions remain unresolved.

Contextual Notes

Participants reference specific integrated circuits that may have limitations due to discontinuation or availability. The discussion includes various assumptions about circuit behavior and configurations that are not fully detailed.

Who May Find This Useful

This discussion may be useful for electronics enthusiasts, students working on circuit design, or individuals interested in integrating binary counters with display technologies.

Tom McCurdy
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We currenlty have a circuit that takes a pulse from a 555 chip and goes through two divide by ten 7490 switchs to create a binary counter that counts up to ten. We are trying to figure out how to convert this binary which we have displayed in regular leds into a 7 segment LED - (LN514rk)

any help would be great.
 
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Don't remember the number but there is a seven segment driver made specifically for this. If you can't find this, set it up using gates to get 10 separate outputs and then diode or those to drive the 7 segment display.
 
You'll need to convert the binary number into BCD and then use a 7447 to convert BCD to 7 segment.

The easy way to convert binary to BCD is to find a 74185 but it has been discontinued. If you can't find that chip you can always program a ROM to do the conversion.
 
dduardo said:
The easy way to convert binary to BCD is to find a 74185 but it has been discontinued.
You could set up the 7490 to do a carry-reset on A(hex).
 
How would we set up the 7490 to do a carry-reset on A(hex)?
 
So the 7446 isn't the way to go on this circuit? We were debating between it and the 7447
 
Alright So what would I need to do if I can't find the 74185 circuit--- Right now again I have a 555 going to two 7490 integratded divide by 10 circuits--- and then I have access to 7447 and 7446 chips is there anything I can do with those to hook up to a 7 segment LED (LN514rk).
 
Tom McCurdy said:
How would we set up the 7490 to do a carry-reset on A(hex)?
Use an AND gate or two. There are a few ways to wire this, depending on the specific behavior you want.

The 7447 should be ok. IIRC the 46 takes a higher output.
The two numbers are much the same. Look up the specs.
 
BTW, is this counting 0-9 or 1-10?
 
  • #10
Averagesupernova said:
BTW, is this counting 0-9 or 1-10?

You can display a "10" on the 7 bit display if you mentally rotate it. A 0 to 11 sequence is possible. I learned this by laying down on the job.:biggrin:


..
 
  • #11
Averagesupernova said:
BTW, is this counting 0-9 or 1-10?
Laying down on the job :smile: :smile: :smile:
10 can be just about any value you can imagine.
Depends on the base you select. :biggrin:
 
  • #12
ok i just now got acess to a 4511 integradted circuit so I am trying to figure out how to use it...
 

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