What is a 74LS139?
The LSTTL/MSI SN54/74LS139 is a high speed Dual 1-of-4 Decoder/De- multiplexer. The device has two independent decoders, each accepting two inputs and providing four mutually exclusive active LOW Outputs. Each decoder has an active LOW Enable input which can be used as a data input for a 4-output demultiplexer.
How demux can be used as decoder?
A decoder with an enable input can function as a Demultiplexer. A demultiplexer is a circuit that receives information on a single line and transmits this information on one of 2n possible output lines. Selection of a specific output line is controlled by the bit values of n selection lines.
What does the Select line of a demux control?
The signal on the select line helps to switch the input to one of the two outputs. The figure below shows the block diagram of a 1-to-2 demultiplexer with additional enable input.
What is the number of select lines required in a 1 N Demux?
of select lines. Therefore, for 1:4 demultiplexer, 2 select lines are required. Explanation: A demultiplexer sends a single input to multiple outputs, depending on the select lines. As the select input changes, the output of the multiplexer varies according to that input.
What is a 2 4 decoder?
The 2-to-4 line binary decoder depicted above consists of an array of four AND gates. The 2 binary inputs labelled A and B are decoded into one of 4 outputs, hence the description of 2-to-4 binary decoder. Each output represents one of the minterms of the 2 input variables, (each output = a minterm).
What is difference between demux and decoder?
Contents: Demultiplexer and Decoder A demultiplexer is a circuit which takes only one input and switches it to one of the several outputs with the help of selection lines. A decoder is the circuit which decodes the input signal fed to it with the help of control signal. A demultiplexer accepts the data as input.
How many select lines would be required for an?
How many select lines would be required for an 8-line-to-1-line multiplexer? Explanation: 2n input lines, n control lines and 1 output line available for MUX. Here, 8 input lines mean 23 inputs. So, 3 control lines are possible.