Digital Electronics help

Thread Starter

aniskazi

Joined May 3, 2014
44
Too complicated????

It's become trivial!
well this is the eq:
For Normal Condition:
A' B' C' + A' B' C + A'B C' + A' BC + A B' C' + A B' C + A B C'

taking A'B' , A'B , AB' as common

A'B'(C' + C) +A'B(C'+C) + A B'(C'+C) + ABC'

A'B' + A'B + AB' + ABC'
Taking A' as common
A'(B'+B) + AB' + ABC'
A' + AB' + ABC'
It is satifsying my truth table as well

this is the final eq right?
and for Warning Buzzer:
ABC
 

WBahn

Joined Mar 31, 2012
29,978
well this is the eq:
For Normal Condition:
A' B' C' + A' B' C + A'B C' + A' BC + A B' C' + A B' C + A B C'

taking A'B' , A'B , AB' as common

A'B'(C' + C) +A'B(C'+C) + A B'(C'+C) + ABC'

A'B' + A'B + AB' + ABC'
Taking A' as common
A'(B'+B) + AB' + ABC'
A' + AB' + ABC'
It is satifsying my truth table as well

this is the final eq right?
and for Warning Buzzer:
ABC
You are making this way, way harder than it is.

Let's say I want to generate a signal Y and I have access to a signal X that is always the opposite of what I want Y to be, how can I generate Y from X?

The problem is that you are being a formula monkey. By that I mean someone that just wants to use memorized or looked-up equations and procedures and turn the crank to blindly get a result. Instead, you need to start looking at the problem and understanding the concepts available to you. Remember, engineers are problem solvers, not crank turners.
 

Thread Starter

aniskazi

Joined May 3, 2014
44
You are making this way, way harder than it is.

Let's say I want to generate a signal Y and I have access to a signal X that is always the opposite of what I want Y to be, how can I generate Y from X?

The problem is that you are being a formula monkey. By that I mean someone that just wants to use memorized or looked-up equations and procedures and turn the crank to blindly get a result. Instead, you need to start looking at the problem and understanding the concepts available to you. Remember, engineers are problem solvers, not crank turners.
I completely understand what you mean with the formula monkey that I'm just rushing into formulas making equations and truth table but I've got my digital electronics exam this week and I need good amount of marks just to pass so I'm just a little nervous... and our professor has taught us to make digital systems only using truth tables than getting equations and making the system for that eq so I'm just trying to follow that... and
I'm trying to understand the question so here is what I understood:


There are three containers and a total of 12 ingredients i.e : From A - L now the mixing system should take any two ingredients and it has to choose from those 12 ingredients kept in 3 different containers and mix it for normal condition but if it takes 3 ingredients than the warning buzzer should go off right?
 
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Thread Starter

aniskazi

Joined May 3, 2014
44
one thing more... well the question says that the ingredients should be taken from 3 different containers in a proper proportion so by proper proportion it means that the mixer should take 1 ingredient from each container and the rest two ingredients from the other two containers right?
 

tshuck

Joined Oct 18, 2012
3,534
I don't think you need to worry yourself about proper proportion, I think that was put in there to say that this step is already taken care of.

[...] but if it takes 3 ingredients than the warning buzzer should go off right?
Yes, and should do what when the buzzer is not active?
 

Thread Starter

aniskazi

Joined May 3, 2014
44
I don't think you need to worry yourself about proper proportion, I think that was put in there to say that this step is already taken care of.

Yes, and should do what when the buzzer is not active?
it should be normal when the buzzer is not active
than this will be the eq:
For Normal Condition:
A' B' C' + A' B' C + A'B C' + A' BC + A B' C' + A B' C + A B C'

taking A'B' , A'B , AB' as common

A'B'(C' + C) +A'B(C'+C) + A B'(C'+C) + ABC'

A'B' + A'B + AB' + ABC'
Taking A' as common
A'(B'+B) + AB' + ABC'
A' + AB' + ABC'
It is satifsying my truth table as well

this is the final eq right?
and for Warning Buzzer:
ABC
this will be my eq according to which I'll have to make my digital syste, am I right?
 

WBahn

Joined Mar 31, 2012
29,978
it should be normal when the buzzer is not active
than this will be the eq:
For Normal Condition:
A' B' C' + A' B' C + A'B C' + A' BC + A B' C' + A B' C + A B C'

taking A'B' , A'B , AB' as common

A'B'(C' + C) +A'B(C'+C) + A B'(C'+C) + ABC'

A'B' + A'B + AB' + ABC'
Taking A' as common
A'(B'+B) + AB' + ABC'
A' + AB' + ABC'
It is satifsying my truth table as well

this is the final eq right?
and for Warning Buzzer:
ABC
this will be my eq according to which I'll have to make my digital syste, am I right?
If you are just going to repeat what you said in Post #21, then I guess it's only reasonable to repeat what I said in Post #22.

You are making this way, way harder than it is.

Let's say I want to generate a signal Y and I have access to a signal X that is always the opposite of what I want Y to be, how can I generate Y from X?

Answer that question and, if you are willing to think about it just a little bit, you will see that you can generate your Normal signal from your Buzzer signal with a single gate.
 

tshuck

Joined Oct 18, 2012
3,534
You may want to look at your max-terms when the number of min-terms is comparable to the total number of input combinations.

While your answer may implement the function, looking at it from another perspective can result in huge savings in the number of gates required.
 

Thread Starter

aniskazi

Joined May 3, 2014
44
If you are just going to repeat what you said in Post #21, then I guess it's only reasonable to repeat what I said in Post #22.

You are making this way, way harder than it is.

Let's say I want to generate a signal Y and I have access to a signal X that is always the opposite of what I want Y to be, how can I generate Y from X?

Answer that question and, if you are willing to think about it just a little bit, you will see that you can generate your Normal signal from your Buzzer signal with a single gate.
I am repeating the same stuff cause I want one particular answer...
and the answer to your question maybe is to use an inverter because Y is opposite of X. My input is X so when I invert it I get Y from X.
Okay so I think I know where you're going with this... as the warning buzzer will go on when ever all the inputs are HIGH so lets say the warning buzzer is X and Y is the normal operation so X is always opposite of Y and so when X is true warning buzzer is on otherwise for all operations normal condition goes ON.
 
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Thread Starter

aniskazi

Joined May 3, 2014
44
You may want to look at your max-terms when the number of min-terms is comparable to the total number of input combinations.

While your answer may implement the function, looking at it from another perspective can result in huge savings in the number of gates required.
Hey this is the simplest system I can make now please check it out it is satisfying all the equations as well :)

sorry but I don't know why but I can't upload the image directly here.

http://postimg.org/image/uq9uzxl93/
 

tshuck

Joined Oct 18, 2012
3,534
Hey this is the simplest system I can make now please check it out it is satisfying all the equations as well :)
A warning buzzer and a buzzer to indicate normal operation? That just be one annoying machine to operate! ;)

Assuming the box is a 3 input AND gate, the circuit matches the functionality of your table.

This can also be done with two, 2-input AND gates and a NOT gate.

sorry but I don't know why but I can't upload the image directly here.

http://postimg.org/image/uq9uzxl93/
Click the small paperclip icon when posting, then upload the image. Then you can copy the URL from the link that's created and paste it into the image dialog window.

Now you can work on making the sensor logic.
 

Thread Starter

aniskazi

Joined May 3, 2014
44
A warning buzzer and a buzzer to indicate normal operation? That just be one annoying machine to operate! ;)

Assuming the box is a 3 input AND gate, the circuit matches the functionality of your table.

This can also be done with two, 2-input AND gates and a NOT gate.


Click the small paperclip icon when posting, then upload the image. Then you can copy the URL from the link that's created and paste it into the image dialog window.

Now you can work on making the sensor logic.
Hey well the circuit can be further simplified but please no :p I'm happy with this one :p
and the answer is complete right? what do you mean by "Now you can work on making the sensor logic"?
 

WBahn

Joined Mar 31, 2012
29,978
Hey this is the simplest system I can make now please check it out it is satisfying all the equations as well :)

sorry but I don't know why but I can't upload the image directly here.

http://postimg.org/image/uq9uzxl93/
But if the signal labeled Warning Buzzer is always the opposite of what you need for the Normal Light, why can't you use an inverter to generate the Normal Light signal from the Warning Buzzer signal?

In practice, you probably wouldn't even do this, but rather design the buzzer circuit and the light circuit so that one is active high and the other is active low.
 

Thread Starter

aniskazi

Joined May 3, 2014
44
But if the signal labeled Warning Buzzer is always the opposite of what you need for the Normal Light, why can't you use an inverter to generate the Normal Light signal from the Warning Buzzer signal?

In practice, you probably wouldn't even do this, but rather design the buzzer circuit and the light circuit so that one is active high and the other is active low.
By saying to generate the normal light from warning buzzer like this:



and about the second one that one should be active high and the other should be active low...
so that is what's happening in the previous circuit I made right? when warning buzzer was HIGH the other was low that is what you mean by active high and low right?
 

WBahn

Joined Mar 31, 2012
29,978
What's the purpose of the OR gate in your diagram?

You have two active-HI signals. The buzzer should sound when the buzzer signal is HI while the LED should light with the normal signal is HI.

What I'm talking about would be a circuit in which the buzzer sounds if its input signal is HI while the LED lights if it's input signal is LO (or the other way around). Then you can just route the same signal to both circuits.
 

Thread Starter

aniskazi

Joined May 3, 2014
44
What's the purpose of the OR gate in your diagram?

You have two active-HI signals. The buzzer should sound when the buzzer signal is HI while the LED should light with the normal signal is HI.

What I'm talking about would be a circuit in which the buzzer sounds if its input signal is HI while the LED lights if it's input signal is LO (or the other way around). Then you can just route the same signal to both circuits.
I understand what youre saying so for active high and low I'll use two and gates with no inverters just AND gates right the OR gate is replaced by AND inverter is removed ao when ever inputs all hihigh warning goes off and when ever any one of the input is low the nornal condition gets a low on it ;) right?
 

WBahn

Joined Mar 31, 2012
29,978
I understand what youre saying so for active high and low I'll use two and gates with no inverters just AND gates right the OR gate is replaced by AND inverter is removed ao when ever inputs all hihigh warning goes off and when ever any one of the input is low the nornal condition gets a low on it ;) right?
This makes about as much sense to me as if it were written in ancient Greek.
 

Thread Starter

aniskazi

Joined May 3, 2014
44
This makes about as much sense to me as if it were written in ancient Greek.
Haha lol sorry about that. What I said was this :

Remove the OR gate and place an AND gate. Remove the inverter as well. So when warning is active HIGH the normal condition is OFF as I need an active low on normal. Right?
 

tshuck

Joined Oct 18, 2012
3,534
Haha lol sorry about that. What I said was this :

Remove the OR gate and place an AND gate. Remove the inverter as well. So when warning is active HIGH the normal condition is OFF as I need an active low on normal. Right?
I think the direction we are headed here is, what is anything ORed with itself?

a+a = ?

Then realize you are doing this to the normal operation indicator signal.

what do you mean by "Now you can work on making the sensor logic"?
The "should" wording in your initial post regarding the sensors Ia, Ib, and Ic sounds like requirements which leads me to think you are supposed to design these too.

Remove the OR gate and place an AND gate.
...to what end?

What is a*a=?

What WBahn is saying is that one would typically make the warning buzzer active high (activated by a logic 1) and the normal operation indicator active low (activated by a logic 0), or vice versa, so the two outputs are determined by the state of a single output.
 
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