four way traffic light - help

Thread Starter

Eng Ranya Salem

Joined Dec 1, 2016
33
What voltage is required to turn on the Y/EW LED and the others in series with it?

The fact that you're a student and this is school work makes this homework. Anything that you will be graded on is considered homework. You can call it a project or anything you want, but that doesn't change the fact that it's work for which you will receive a grade. Most schools have an official policy on taking the work of others and claiming it's yours.
I'm not a School Student and I'm not an Electrical Engineer to know Most of this Circuit
I tried to draw the design in the picture but it didn't work
So I tried to ask someone who know
this is not a guilt
I'm 28 years old So I graduated from Fac Of engineering 6 years ago

I need the test of this Circuit for something in my work in Master Degree ( it is not my specialty but I tried to draw the circuit , I didn't request it from Electrical engineer , I try by my self )

Thanks dear
Thanks for your help
 

dl324

Joined Mar 30, 2015
18,376
I need the test of this Circuit for something in my work in Master Degree ( it is not my specialty but I tried to draw the circuit , I didn't request it from Electrical engineer , I try by my self )
Sounds like this conforms to my definition of homework.

You still haven't answered my last question. What voltage does the cathode of the top Y/EW LED need to be at for it and the LEDs in series with it to turn on?
 

Thread Starter

Eng Ranya Salem

Joined Dec 1, 2016
33
Sounds like this conforms to my definition of homework.

You still haven't answered my last question. What voltage does the cathode of the top Y/EW LED need to be at for it and the LEDs in series with it to turn on?
as you like :)

I don't know the voltage required !! how to measure it ?
 

bertus

Joined Apr 5, 2008
22,941
Hello,

In post #11 the model timing voltage is at 5 Volts.
Did you select 12 Volts there?

Bertus

PS I moved the thread to homework.
No matter if it is a project, it is still for school.
 

bertus

Joined Apr 5, 2008
22,941
Hello,

The shot taken in post #11 shows a model timing voltage of 5 Volts.
With that voltage the leds will never work.

Bertus
 

Thread Starter

Eng Ranya Salem

Joined Dec 1, 2016
33
Hello,

In post #11 the model timing voltage is at 5 Volts.
Did you select 12 Volts there?

Bertus

PS I moved the thread to homework.
No matter if it is a project, it is still for school.
as you like , The most important form me to get the result of the circuit
Thanks :)
 

dl324

Joined Mar 30, 2015
18,376
I don't know the voltage required !! how to measure it ?
I'm not familiar with the simulator you're using.

And I misspoke. It would be simpler to specify the voltage required on the anode of the top Y/EW LED.

What is the forward voltage of each of the LEDs in series with the Y/EW LED? That will tell you what voltage you need at the cathode of the OR'ed diodes for turn on.

EDIT: The Y/EW LED chain is being driven by Q9 and there are no OR'ed diodes for that chain. But same question.
 

dl324

Joined Mar 30, 2015
18,376
So what voltage do you need on the anode of the top Y/EW LED to turn it and the other two LEDs in series with it?

What current do you want in the LEDs?

How much current can the outputs of the 4017 source?
 

dl324

Joined Mar 30, 2015
18,376
I can read the datasheet just fine. I'm asking you to do it.

You still haven't stated what voltage is required at the output of Q9 to turn on the LEDs; or stated the current you want in them.
 

wayneh

Joined Sep 9, 2010
18,121
The 555 will run at about 7Hz, meaning your light sequence will cycle in just over 1 second. Is that your plan?

Have you verified that the 555 is running as expected?

If it is, watch the output pins of the 4017. Are they behaving as expected? Instead of the confusing arrangement there now, try using an LED to ground on each output pin. Move all those diodes off to the side for while, until you have sorted out what is happening. You can use a single resistor to ground for all of the output LEDs, since only one will be on at a time, but even that's not necessary since the 4017 cannot source enough current to harm an LED anyway.

Once you get the 555 and the 4017 operating as planned, then you can experiment with more complex LED arrangements.
 

Thread Starter

Eng Ranya Salem

Joined Dec 1, 2016
33
The 555 will run at about 7Hz, meaning your light sequence will cycle in just over 1 second. Is that your plan?

Have you verified that the 555 is running as expected?

If it is, watch the output pins of the 4017. Are they behaving as expected? Instead of the confusing arrangement there now, try using an LED to ground on each output pin. Move all those diodes off to the side for while, until you have sorted out what is happening. You can use a single resistor to ground for all of the output LEDs, since only one will be on at a time, but even that's not necessary since the 4017 cannot source enough current to harm an LED anyway.

Once you get the 555 and the 4017 operating as planned, then you can experiment with more complex LED arrangements.
After Adding Ground to all out for each LED
but it still not lighting

what do you think ?

 
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