Encoding means
converting one form of
data to another type.
Here we are converting
decimal to binary.
When the 1 button is
pushed, D1 is forward
biased and the least
significant bit goes
high. D4 is reverse biased and
blocks the + 5 volts
from the other lines.
When the 2 button is
pushed, D2 conducts and
takes the middle bit
high. D3 again blocks the + 5
volts.
When button 3 is pushed,
D3 and D4 conduct and
take the two lower bits
high.
With three lines you can
have the binary numbers
000 to111 (decimal 0 to
7) encoded.
![Encoders Diagram](images/encoder.gif) |