What is the need of decoder make a 3/8 decoder using 2 to 4 decoder?

Therefore, we require two 2 to 4 decoders for implementing one 3 to 8 decoder. The block diagram of 3 to 8 decoder using 2 to 4 decoders is shown in the following figure. The parallel inputs A1 & A0 are applied to each 2 to 4 decoder.

Which of the following can be used to construct the 3 to 8 line decoder?

The implementation of this 3 line to 8 line decoder can be done using two 2 lines to 4 line decoders. We have discussed above that 2 to 4 line decoder includes two inputs and four outputs. So, in 3 lines to 8 line decoder, it includes three inputs like A2, A1 & A0 and 8 outputs from Y7 – Y0.

How many and gates are required for a 3 to 8 decoder?

Using the above expressions, the circuit of a 3 to 8 decoder can be implemented using three NOT gates and eight 3-input AND gates as shown in fig (1). The three inputs A, B and C are decoded into eight outputs, each output representing one of the midterms of the 3-input variables.

What is a 2 to 4 line 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 the maximum number of outputs of a 3 to 8 line decoder that can be active at once?

A 3-to-8 line decoder activates one of eight output bits for each input value from 0 to 7 — the range of integer values that can be expressed in three bits. Similarly, a 4-to-16 line decoder activates one of 16 outputs for each 4-bit input in the integer range [0,15].

How do you design a 3/8 decoder using a 4/16 decoder is it possible?

4 to 16 decoder circuit is obtained from two 3 to 8 decoder circuits or three 2 to 4 decoder circuits. When two 3 to 8 Decoder circuits are combined the enable pin acts as the input for both the decoders. When enable pin is high at one 3 to 8 decoder circuits then it is low at another 3 to 8 decoder circuit.

What is a 2 4 decoder?

A 2-to-4 Binary Decoders This simple example above of a 2-to-4 line binary decoder 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.

How do you make a 2 to 4 decoder?

What are the input pins of the IC 74138?

1. The pin no. 8 and 16 are the ground and Vcc respectively for the power input. 2. There are a total of three input pins (pin no. 1, 2, 3). They are denoted by A0, A1, A2. So the IC 74LS138 can take three binary input signals. 3. There are three enable input pins E1, E2, E3 (pin no. 4, 5, 6).

How to design a 3 by 8 decoder using only two ( 2 by 4 ) decoders?

Previous answers explained clearly design of 3 by 8 decoder by using enable input pins of 2 by 4 decoders. However there is another way without using enable pins but with the help of some AND gates and NOT gate. This is just for your information. Let us label out input lines of the 3 to 8 as I0, I1 and I2, and our 8 outputs as Q0..Q7.

How to cascade two 74138 IC’s to implement an active Low decoder?

How to cascade two 74138 IC’s to implement a 4-to-6 active low decoder. IC 74138 works as a 3-to-8 active low decoder,based on the values assigned to three select inputs of the three enable inputs, G1 must be made high value while G 2A and G 2B must be low.

What kind of IC is a logical decoder?

IC 74138 is a Logical Decoder IC. It also has a demultiplexing facility. The IC 74138 is available in the market with the name of 74LS138. It is a 3 to 8 decoder IC.