Why some micro switches have a small circuit board attached to them?

[eeguy]

Hello, while looking for some micro switches for micro-controller, I noticed that some are sold with three pins which we could solder the wires to at one end and attach to a micro-controller at the other end. There are also switches that are sold with a small circuit board (with condenser and resistor) attached. What do those circuit boards do?

[kevin.gibbs]

It may be a protection against contact rattle.

[electr_peter]

It may be a protection against contact rattle.

Yes, most likely PCB is prepared with contact debouncing parts.

[MarkT]

Or a snubber to reduce contact arcing?

[tooki]

It may be a protection against contact rattle.

Yes, most likely PCB is prepared with contact denouncing parts.

I think you’re both referring to contact debouncing. (Yes, I had to override my phone’s autocorrect. )

[Infraviolet]

Often mechanical in its nature, the small board lets one easily fit a wire-to-board connector for one-or-another 2 or 3 wire cable connector system (JST something, Molex something, 2.54mm headers...), you can plug and unplug the cables easily. That compares to trying to directly solder wires to the male pins of the microswitch, not pleasant when you're using multi-cored wire as flexing of it will be cmmon and the wire breaks at the interface between the solder joint and the insulation, and soldered wires can't be as easily attach and removed as cables with headers.