Features:Operating Voltage: 5V Pulse Number for One Circle: 20 Rotary-encoder can count the output pulse time- by rotating positively and negatively. This counting method- has no limitation, it can reset- and come-back to the initial status if matching with the key- on the encoder (that is to say it-will count from 0) Operating Principle: Incremental encoder is a kind of rotary-sensor which transforms the rotations displacement into a series of digital pulse-signal. These pulses are used to control angular- displacement. In Eltra-encoder, the transformation of angular- displacement adopts photoelectric scaning principle. The reading system is based-on the radial-dividing plate rotations of alternative light window and non-light window, and it will be exposed to infrared-light source at the same-time. The light will reflect the picture of plate on the surfaces of receiver. The receiver is covered- by a diffraction- grating, and it has the same window width with the plate. The operation of receiver is to detect the change of light plate rotations, then transform the light change into electric change. Increase the low level signal into high level and generate square pulse without any interference. This process needs circuit to deal with. The reading system usually adopts differential methods, that is compare two different signals who have the same waveform bu- the phase difference is 180 degree so as to improve the output signal quality and stability. Reading is formed on the basis of the difference between two signals, so it eliminates the interference. Specifications:Material:PCB Note:Please allow 1mm errors due to manual measurement. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes:1x Rotary Encoder