A rotary encoder, also called a shaft encoder, is an electro -mechanical device that converts the angular position or motion of a shaft or axle to analog or digital output signals. There are two main types of rotary encoder : absolute and incremental. https://youtu.be/XCBteRWZs5k? Specifications: Supply Voltage:4.75 to 30 V DC Output Voltage("H"):[(Supply Voltage) -2.5 V] or more Output Voltage("L"):0.4 V or lower Output Current(Sink "L"):Up to 30 mA Output Current(Source "H"):Up to 10 mA Package Include: 1 x KOYO Rotary Encoder TRD-J5000-RZ