Digital Electronics - Combinational Logic Circuits - Discussion

1. 

How many 3-line-to-8-line decoders are required for a 1-of-32 decoder?

[A]. 1
[B]. 2
[C]. 4
[D]. 8

Answer: Option C

Explanation:

No answer description available for this question.

Muhdin Abdo said: (Dec 18, 2010)  
The 3-input data lines used as common lines for the 4-decoder of 8-out puts. Thus, one could have a total of 4*8=32 out puts. Hence one needs 4 a 3-line-to-8-line decoders.

Ravi Kumar Sinha said: (Sep 27, 2011)  
In order to have 32 output lines you need to have 4 3*8 decorder and for the input you can connect enable and enable bar to four different different decorder so that we can different configuration for 1 input lines.

Ayyappa said: (Jul 5, 2014)  
Required outputs/given outputs == (32/8) = 4.

Ajay Kumar said: (Aug 30, 2016)  
I think 1 to 32 means 5 by 32.

32/8 = 4 decoders sufficient but what about inputs?

Now inputs are 12 (4 decoders * inputs 3) , so again we need 2 decoders to complete the circuit.

Ravi said: (Jan 9, 2017)  
Explain in the form of diagram eg. decoder.

Amareswari said: (Jan 20, 2017)  
We need one 2 to 4 decoder and four 3 to 8 decoders to implement 5 to 32 decoder.

Mvp said: (Mar 20, 2017)  
Decoders having 2^m outputs and m inputs w.r.t this to obtain 32(2^5) output lines we need 5input lines.

How come you can make 1-32 decoder?

Rajaram said: (Sep 14, 2017)  
Decoder can be used as demultiplexer also, so 1x32 demux is similar to 5x32 decoder. Here 3x8 decoders (4x8 =32 outputs) input is single line. So 2 input line is used in chip selection one of 4 chip.

Keerthi said: (Sep 15, 2017)  
Your explanation is simple and clear to understand @Ayyappa.

Rajashekar said: (Sep 20, 2017)  
(32÷8) + (4÷8) =4.5.

So, the answer is 4.

Ann said: (Nov 25, 2018)  
What is a demultiplexer?

Suren said: (Jul 20, 2019)  
5 input lines is the correct answer.

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