A push-button (often simply "button" or "pushbutton") is a simple
switch mechanism for
controlling some aspect of a
machine or a
process. Buttons are typically made out of hard material, usually
plastic or
metal. The surface is usually flat or shaped to accommodate the human finger or hand, so as to be easily
depressed or
pushed. Buttons are most often biased switches, though even many un-biased buttons (due to their physical nature) require a
spring to return to their un-pushed
state.
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