GATE Electrical Engineering (EE) Test: Encoders Free Online Test 2026

An encoder is a combinational circuit encoding the information of 2n input lines to n output lines, thus producing the binary equivalent of the input. Thus, a Decimal-to-bcd converter has decimal values as inputs which range from 0-9. So, a total of 10 inputs are there in a decimal-to-BCD encoder.

An encoder is a combinational circuit encoding the information of 2ⁿ input lines to n output lines, thus producing the binary equivalent of the input. It performs the opposite operation of a decoder which results in 2ⁿ outputs from n inputs. Thus, an encoder different from a decoder because of the output of an encoder is a binary code for 1-of-N input.

Of course, a transducer is a device that has the capability to emit data as well as to accept. Transducer converts signal from one form of energy to another.

An encoder is a combinational circuit encoding the information of 2ⁿ input lines to n output lines, thus producing the binary equivalent of the input. Thus, in octal to binary encoder there are 8 (= 23) inputs, thus 3 output lines.

Such problems are resolved by using enable input, which behaves as active if it gets 0 as input since it is an active-low pin.

If we record any music in any recorder, it means that we are giving data to a recorder. So, such process is called encoding. Getting back the music from the recorded data is known as decoding.

An encoder is a combinational circuit encoding the information of 2ⁿ input lines to n output lines, thus producing the binary equivalent of the input.
This is clear from the diagram that it requires 4 OR gates:

Concept:

A magnitude digital Comparator is a combinational circuit that compares two digital or binary numbers in order to find out whether one binary number is equal, less than or greater than the other binary number. We logically design a circuit for which we will have two inputs one for A and another for B and have three output terminals, one for A > B condition, one for A = B condition, and one for A < B condition.

Application:

1-Bit Magnitude Comparator:

A comparator used to compare two bits is called a single bit comparator. It consists of 2-inputs each for two single-bit numbers (0 or 1) and 3-outputs to generate less than, equal to and greater than between two binary numbers.

The truth table for a 1-bit comparator is given below:

• The encoders are used for coding binary data. The encoder is a combinational logic circuit that converts an active input signal into a coded output signal.
• It has n input lines, only one of which is active at any time and m output lines. It encodes one of the active inputs to a coded binary output with m bits. In an encoder, the number of output lines is less than the number of inputs. If an encoder has n input lines and m output lines than n<= 2^m.

Example:

For 8 × 3 Encoder

n = 8

m = 3

8 = 2³

n = 2^m

For 7 × 3 Encoder

n = 7

m = 3

7 < 2³

Take 2 numbers for 17 bits, for the first 2 bits of each number we need one-half adder and for rest(16 bit of each number) we will have one carry of previous sum and two bits of each number so we need one full adder for each rest of bits, that is, 16 full adder.