A clear study of encoders and decoders and their types with their applications

1. Deepika D G
I M.Sc Physics
Alagappa University

2. OBJECTIVES
 Encoders
 Decimal to BCD encoder
 Priority encoders
 Decoders
 BCD to Decimal Decoder
 Seven Segment Decoder
 1-16 Decoder
 Applications

3. Encoders
 An encoder is a device which transforms the data into some bits
(binary numbers).
 OR gates are mostly used in encoders.
 The process of converting input data into binary code is called
Encoding and the circuit used is known as an Encoder .

4. Decimal to BCD Encoder
A decimal to BCD(binary coded decimal) encoder is
also known as 10-4 line encoder.
 It accepts 10 inputs and produces a 4 bit output
corresponding to the decimal input.

5. In this encoder, the decimal digits are converted into the four bit Binary Coded Decimal
(BCD). The four bits are named as A, B, C and D. The most significant digit is ‘A’.
It has four 4- input OR gates. The outputs are named as A, B, C, D (BCD output).
When a particular button is pressed ,the corresponding binary output is available at the end of
OR gates.

6. .
A priority encoder is a circuit or algorithm that
compresses multiple binary inputs into a smaller
number of outputs.
If 2 or more inputs are equal to 1 at the same time,
the input having the highest priority will take
precedence.
Internal hardware will check this condition and
priority is set.
Priority Encoder

7. DECODER
 A decoder is a logic circuit that accepts a set of inputs that represents a binary
number and activates only the output that corresponds to the input number.
 It converts binary input to decimal output.
 The decoder is used in the output of the computer mostly.
 An AND gate can be used as the basic decoding element because it produces a high
output only when all inputs are high.

8. BCD to Decimal Decoder
It converts the BCD code into its decimal equivalent number.
The logic
circuit for the
implementation
of a decimal
number in the
decoder can be
obtained by
forming a
combination of
high bits.

9. Seven Segment Decoder
Seven segment display is the most popular display device
used in all digital system. The numeric result appear on a
visual display as the decimal numbers. For displaying a result
data using this device , the data have to be converted to
7segment code from BCD. A seven segment indicator
consist of 7 LEDs with one diode for each segment. LEDs
emit light when they are forward biased.

10. Example: To display the number 0, we need a,b,c,d,e,f .
To perform this action, the segments should be
illuminated and this could be achieved only by forward biasing
the diodes in a,b,c,d,e,f.
This could be also done with the help of a decoder driver. This
is mostly used in digital voltmeters and electronic calculators.

11. 1 of 16 Decoder
This decoder is similar to that of a demultiplexer.
The circuit is called as 1 of 16 because only 1 of the 16 lines
will be high. It can either act as a decoder or as a
demultiplexer.

12. APPLICATIONS OF
ENCODER’S,DECODER’S
1. Data communications
2. Data compression
3. Data privacy and security
4. Make data human readable
5. Data scans