An encoder converts human-readable characters or symbols into a digital format that digital systems can understand. It is a digital logic circuit with as many inputs as different characters to encode and as many outputs as bits in the encoded format. Encoding reduces the number of data lines needed for transmission. Priority encoders assign priority levels to each input, so the output corresponds to the active highest priority input, ignoring lower priority inputs.

1. Encoder
• When we insert any character or symbol to a digital system, through key board, it
is needed to be encoded in machine readable farm.
• Digital systems like computer etc, cannot read the characters or symbol directly.
The system reads and computes any characters, numbers and symbols in their
digital form.
• An encoder does the job that means, it converts different human readable
characters or symbol to their equivalent digital format.
• An encoder is basically multi inputs and multi outputs digital logic circuit, which
has as many inputs as the number of character to be encoded and as many
outputs as the number of bits in encoded form of characters.
• Encoding can be used to minimize the number of data lines required for signal
transmission. A particularly useful application for encoding is the translation of
input devices into binary code.

3. 4-to-2 Bit Binary Encoder

5. Priority Encoder
• The Priority Encoder solves the problems mentioned above by
allocating a priority level to each input.
• The priority encoders output corresponds to the currently active
input which has the highest priority. So when an input with a
higher priority is present, all other inputs with a lower priority will
be ignored.
• The priority encoder comes in many different forms with an
example of an 8-input priority encoder along with its truth table
shown below.

6. 8-to-3 Bit Priority Encoder