how many bits are required for a four-input multiplexer?

Question

anonymous · Answer

um i dint get the qn.....but if u have 4 inputs....then u l need two switches so smthing like 4+2?

nick67 · Answer

you need two bits to select one of the four input channel: 00, 01, 10, 11

anonymous · Answer

thank all......

nick67 · Answer

you are welcome

anonymous · Answer

r u a computer scientist??

nick67 · Answer

hy msamido, is it a question for me ?

anonymous · Answer

yes..

nick67 · Answer

no, I'm just an engineer in Electronics

anonymous · Answer

nick67 @nick67 ummm a 4 pin multiplexer must have 4 inputs/bits  can you show me an equation or truth table for a 4 pin multiplexer that only needs 2 input bits? logically this makes no sense to me because using your logic you could just as well have 1 bit going in. I probably wrong though I gonna google it some more...maybe you can explain before I find the answer. --calmchess

nick67 · Answer

hi @calmchessplayer , let me better explain my point of view; speaking of a multiplexer (MUX), we may have an analog MUX or a digital MUX. In both cases we have more inputs and one output. Within the multiplexer we have a multi-position switch ( S ) that can close the connection between one of the input channels and the only output. The command logic needs as many bits to select the input channel as the following relation says:
$$n _{bit} = \log_{2} (inCh)$$
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