Function of enable input in gates

In summary, the enable input in gates allows input pulses to pass from input to output if it is low. This only applies to an OR gate, as other gates have different functions. When the enable input is high, the output will always be high regardless of the other input. This allows for the creation of a frequency counter by counting pulses that pass through the gate when the enable input is low for a specific duration.
  • #1
waqarrashid33
77
0
what are the function of enable input in gates?


If in or gate we use it and it is at high and the other two inputs are at low then what will be out put...1/0?
Please clear me about the enable input
 
Engineering news on Phys.org
  • #2
If either input of an OR gate is high, then the state of the other input doesn't matter. The output will be high.

To allow input pulses to pass from input to output of the gate, then the "enable" input has to be low.

This input pin is no different to any other pin on the gate input, but its function makes it an "enable" (or disble) pin.
 
  • #3
when the enable is at low the gate/I.C will be disable and when the enable is at high the gate/IC will be disable...but told that To allow input pulses to pass from input to output of the gate, then the "enable" input has to be low...what is correct..if you have any external link about it then please provide it..
 
  • #4
waqarrashid33, for a good explanation of the "enable" function of logic gates see:

http://www.allaboutcircuits.com/vol_4/chpt_3/8.html
 
Last edited:
  • #5
This only applies to an OR gate. Other gates are different.

http://en.wikipedia.org/wiki/Or_gate

As you can see, with an OR gate, if either or both of the inputs are high, then the output will be high. If they are both LOW, the output will be LOW

So, if you make one of the inputs LOW, then the output will depend on what the other input does.
If it is HIGH, the output will be HIGH, and if it is LOW, the output will be LOW.

Now, if you make the enable input HIGH, what can happen?
If the other input is LOW the output will be HIGH.
If the other input is HIGH, the output will be HIGH.
So the output will always be HIGH.

So, even if you put pulses (ie HIGH, LOW, HIGH...) on the other input, none of them will get through to the output.

That is why they call it a gate. It can let stuff through or stop it.

So what use is all this?
If you made the enable input LOW for exactly 1 second, you could use another circuit to count how many pulses got through and display this number on a display of some sort.
You would then have a frequency counter.
 

What is the function of an enable input in a gate?

The enable input in a gate controls when the gate is allowed to operate. When the enable input is turned on, the gate will function as normal. When the enable input is turned off, the gate will not function and its output will remain unchanged.

How does an enable input affect the output of a gate?

When the enable input is turned on, the gate will operate according to its normal function and the output will be determined by the inputs. When the enable input is turned off, the gate will essentially be "disabled" and its output will remain unchanged.

In what types of gates is an enable input commonly found?

Enable inputs are commonly found in sequential logic gates, such as flip-flops and latches. These gates require an enable input to control the timing and sequence of their operations.

Can the enable input of a gate be used to selectively enable certain inputs?

Yes, the enable input can be used to selectively enable certain inputs in a gate. This allows for more control over the gate's operation and can be useful in certain applications.

What happens if the enable input is left floating or disconnected?

If the enable input is left floating or disconnected, it may result in unstable or unpredictable behavior of the gate. It is important to properly connect and control the enable input to ensure the gate's proper function.

Similar threads

Replies
2
Views
815
Replies
4
Views
823
  • Electrical Engineering
Replies
5
Views
1K
Replies
80
Views
3K
  • Electrical Engineering
Replies
3
Views
1K
  • Electrical Engineering
Replies
3
Views
2K
  • Electrical Engineering
Replies
4
Views
318
Replies
3
Views
2K
  • Electrical Engineering
Replies
9
Views
1K
  • Electrical Engineering
Replies
10
Views
492
Back
Top