Digital Electronics - Combinational Logic Circuits - Discussion
Discussion Forum : Combinational Logic Circuits - General Questions (Q.No. 7)
7.
A 74HC147 priority encoder has ten active-LOW inputs and four active-LOW outputs. What would be the state of the four outputs if inputs 4 and 5 are LOW and all other inputs are HIGH?
Discussion:
16 comments Page 1 of 2.
Rglokkesh said:
9 years ago
Active high inputs mean the input goes high if it is open, and requires the previous stage driving the input to sink current in the low state to pull the input low to from a logical zero.
The active low output means that the output in the low state can sink current.
The active high output means that the output can source current in the high state.
All TTL parts are active high input and active low output.
The active low output means that the output in the low state can sink current.
The active high output means that the output can source current in the high state.
All TTL parts are active high input and active low output.
Bhasky said:
9 years ago
In priority encoder, the o/p is based on priority (high priority). In the given i/p both 4 and 5 i/p's are active so, based on priority it will consider 5 as o/p. So, the o/p is 0101.
Baz said:
7 years ago
This is wrong the answer should be C because with 0101 the LSB is A0 and MSB is A3 the answer A is technically 1010 which is a decimal 10.
(1)
Nikhila said:
4 years ago
For the priority encoder, priority is increasing from 0 to 10. Here we giving 5 and 4 as zero, so priority is higher for 5.
5 = 0101.
5 = 0101.
Bijendra Kumar said:
1 decade ago
As two Inputs are low, I4 is given priority(5th i/p), so respective o/p 0101 represents 5. So, it is the correct answer.
Harish TR said:
2 years ago
@All.
Here we are using the BCD value at the output it's not a normal encoder it is different.
Here we are using the BCD value at the output it's not a normal encoder it is different.
Vishal rana said:
1 decade ago
Active low means when logic is 0 apply then it is consider 1.
(high) & vice verse.
(high) & vice verse.
Nehal said:
10 years ago
It means it will be active when output is low (=0). Only then it shows us the output.
Dudin said:
3 years ago
@Bijendra Kumar.
Why the priority is higher in I4 and not I5?
Why the priority is higher in I4 and not I5?
Macky said:
10 years ago
I'm confuse about the active low output, please explain.
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