What is the need of decoder make a 3/8 decoder using 2 to 4 decoder?
What is the need of decoder make a 3/8 decoder using 2 to 4 decoder?
3 to 8 Decoder We know that 2 to 4 Decoder has two inputs, A1 & A0 and four outputs, Y3 to Y0. Whereas, 3 to 8 Decoder has three inputs A2, A1 & A0 and eight outputs, Y7 to Y0. We can find the number of lower order decoders required for implementing higher order decoder using the following formula.
What is enable in decoder?
Decoders with Enable A standard decoder typically has an additional input called Enable. Output is only generated when the Enable input has value 1; otherwise, all outputs are 0. Many components have an Enable input which works in this way. Sometimes the Enable input is “active high”, sometimes “active low”.
How many and gates are required to implement a 3 to 8 decoder with an enable?
three NOT gates
From the above Boolean expressions, the implementation of 3 to 8 decoder circuit can be done with the help of three NOT gates & 8-three input AND gates. In the above circuit, the three inputs can be decoded into 8 outputs, where every output represents one of the midterms of the three input variables.
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 labeled A and B are decoded into one of 4 outputs, hence the description of a 2-to-4 binary decoder. Each output represents one of the minterms of the 2 input variables, (each output = a minterm).
Why is enable used?
An Enable will allow an input signal, shown in green, to pass the output, shown in red, when the control signal is high. It will prevent a signal from passing when the control signal is switched to low.
How do you make 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).
How many 2/4 decoders will be used to design a 4/16 decoder with an enable input?
Assuming all the 2×4 decoders have an enable input, which activates the decoder when the input to it is logic high, 5 such decoders would be required as shown below. A 4×16 decoder has 4 inputs and 16 outputs, with the outputs going high for the corresponding 4-bit input.
How many 2 to 4 line decoders with an enable input are required to construct a 4 to 16 line decoder without using any other logic gates?
If we are really talking about 74139 style 2 line to 4 line decoders you need 5 of them. Four provide the 16 outputs and the fifth one selects which of the first 4 is active.
