Rotary Encoders

Different types of encoders for different machines and different behavior with different voltage range, analogue or digital are available and rates are provided on inquiry and cheaper rates than market are available.
There are mainly two types of encoders absolute encoders and Incremental encoders.
Absolute encoders tell the position of shaft while incremental encoders tells the speed of shaft.
Here is a image of one encoder TRD-N2000-RZW (KOYO).

Here is Image of open encoder and the source of this image is  https://en.wikipedia.org/wiki/Rotary_encoder