# Digital Electronics - Combinational Logic Circuits - Discussion

### Discussion :: Combinational Logic Circuits - General Questions (Q.No.1)

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

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.

 Adeena said: (Dec 18, 2019) How can 2 to 4 line decoder be used in this? Can you tell by the circuit diagram?