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【Rotary Encoder】These are continuous rotary encoder switch; Type: Encoder code with Switch; Adjustment method: 360 Degree Rotary; Number of digits: 20 digits; Pins: 5.
【Encoder Specification】Shaft Diameter: 6mm/0.24inch; Shaft Length: 20mm/0.79inch; With built in push button switch (push to operate).
【Widely Application】Can be used for data entry as with modern in car CD players, for volume & on/off control or data selection via LED or LCD display; perfect for use with PIC or ATMEL microcontrollers.
【Package Included】5 x 360 Degree Rotary Encoder Code Switch Push Button EC11 Digital Potentiometer + 5 x Knob Cap

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Why are rotary encoders so cool?
Unlike a variable resistor/potentiometer they have infinite travel in any direction and because they produce a digital "Gray code" you can scale their readings to whatever range you like.
The dual direction makes them useful for increasing or decreasing a value within a variable or navigating menus.
Finally, many of these rotary encoders come with a centre push button, which can be used to select menu items, reset a counter or do anything you can think of that might suit a momentary push button.
Specifications:
Rotary Shaft Length: Approx. 12mm
Shaft Overall Length: Approx. 20mm
Shaft Diameter: Approx. 6mm
Dimension (LxW): Approx. 15x12mm
Rated voltage: DC 5V
Max. rated current (Impedance load): Each phase conductor: 0.5mA, Min. 0.5mA
General conductor: 1mA (MAX. 10mA, MIN. 0.5mA)
Position: 20
Pulse: 20
360-degree rotation
Rotational life: Min. 50000 cycles
Switch life: Min. 20000 cycles
Package Included:
5 x 360 Degree Rotary Encoder Code Switch Digital Potentiometer with Switch
5 x Knob Cap