On Monday, October 17, 2016 at 7:25:11 PM UTC-7, Steve Kraus wrote:
> No problem here...just thinking about something.
>
> Growing up, my folks had one of those silent mercury toggle wall switches
> in their bedroom. It was there when we moved in. The regular switches
> around the house made really loud snaps.
>
> Nowadays, switches are nearly all virtually silent.
>
> I presume the difference was all in the detent action not in the switch
> contacts themselves (though one might expect the actual contact material
> having improved).
>
> So they probably could have made the switches silent if they'd wanted to,
> no?
The old snap-action switches were a quick-make/quick-break design with
heavy springs to move the (brass?) contacts rapidly, to minimize
sparking/spark-related metal erosion. You don't erode liquid mercury, it
just evaporates a tiny bit and condenses later.
> Did people back in the day actually want switches to make loud snaps like
> maybe to assure them that the action had taken place?
>
> And when someone did want a silent one, did they not know how to quiet the
> detent? A mercury switch just seems like a lot of trouble if there was an
> easier way.
I think the modern switches use a silver alloy button contact, that lasts a long
time, and doesn't need to be scraped against other metal to keep it clean.
Personally, I like the mercury switches (am using a few in high-use locations).