Analog and Digital Sensors

It produces discrete digital output signal or voltage which is digital representation of quantity to be measured.
It produces binary output in the form of ones (1s) and zeros (0s).
They are used in various applications such as waste water, water and other industrial processes.
Digital sensor consists of sensor itself, cable and a transmitter.
Examples: Measurements such as pH level, conductivity, dissolved oxygen, ammonium, nitrate etc. are conducted using digital sensors.

It produces continuous output signal or voltage which is proportional to quantity to be measured.
It produces analog output.
Quantities such as temperature, speed, displacement, pressure, strain etc. are analog quantities as they are continuous in nature.
Example: Temperature of liquid can be measured using thermometer or thermocouple which continuously responds to changes in temperature as liquid is heated up or cooled down.