MICROSWITCH (aka Cherry switches)

A microswitch is a mechanical device which (somewhere within) contains two contacts.  Microswitches are modular, cheap to produce, dust-and contaminant-resistant, and METERED.  By "metered", I mean to say that it clicks at the same point when the actuator is depressed. Because of the manufacturing tolerances, this consistency will be observed not only for the lifetime of the switch (long!), but for any other microswitch of that model; if the necessity arises to "switch it out", any difference in the "action" will be immeasurably small. these switches, with their characteristic "click", are also often called "Cherry switches" for a leading (THE leading?) producer of such switches. Again, the main advantage of microswitches is durability and consistency.

--- Courtesy DeCosa

Two joysticks with microswitch controls.  Click on picture for larger view.	Arcade pushbuttons with microswitch connections underneath.  These are  vertical mount microswitches.  Horizontal  mount microswitches exist as well (see  joysticks at left).  Click on picture for larger view.

 LEAF

A leaf switch (harder and harder to find!) is essentially two slivers ("leaves") of metal held close together (but separate!) at one end by a non-conductive spacer. The simple act of pushing one piece of metal causes it to bend and touch the other. The disadvantage of the leafswitch is that it is high-maintenance: the leaves gradually "drift" apart (and must be bent back together), its contacts oxidize much more quickly than those of a microswitch, and it has an overall higher breakdown rate. The advantage of a leafswitch is that it is ADJUSTABLE: the "throw" can be adjusted by simply bending one of the metal leaves. (This difference between a micro and leaf switch is much more apparent in joystick applications than in buttons.)

--- Courtesy DeCosa
 

Pushbuttons with leaf style contacts.  Click pictures for larger view.

 PCB

PCB - printed circuit board.  The green board that the electronic components are assembled and joined on.  Usually refers to the main game boards of an arcade machine, but can also refer to any printed circuit board.  For instance, some buttons have small PCB's under them, and monitors have PCB's attached that control them.