Knob is used to adjust parameter value by changing the rotation angle
Variants
- Analog knob (potentiometer)
- Analog knob with off position
- Analog knob with button
- Infinite knob (encoder)
- Tumbler
- Motorized knob
- Knob with sector feedback
Size and ergonomics
Small knobs are rotated by using two fingers, while some large diameter knobs can be rotated by single finger.
It is also important to consider the space around knobs, so that there is space for fingers and no risk to accidentally affect another control. Especially it is important if there is a group of knobs.
Consider, if the user needs to wear safety gloves — it will require more space between controls.
Feedback
Some knobs may provide feedback by using embedded electrical motor. In general, there are two types of feedback:
- If the parameter is changed not by the user, but by the system or third party, or if the user adjusts it by using other method (for instance, by using remote control) then the knob is moved to the corresponding position automatically. Typical examples are Hi-Fi systems, where the user can change the volume by rotating the knob or by using the remote control, and music production controllers, mixers and synths, in which you can load the project and position of knobs and sliders will be adjusted corresponding to the values in the project.
- If the parameter is limited dynamically or there is inertia, the knob resists to the adjustments by the user when certain limit is reached. These are used in maritime systems when the user operates azipod thrusters, also in handling industrial robot’s arms and other specific control tasks.