Mercury Wall Switch

[Steve Kraus]

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?

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.

 

[whit3rd]

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).

 

[isw]

In article <m4ydncmuEYedFZjFnZ2dnUU7-YHNnZ2d@earthlink.com>,
Steve Kraus <screen@SPAMBLOCKfilmteknik.com> 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?

Did people back in the day actually want switches to

In the beginning (of electrical service) a given household or area might
be fed with DC. Without the regular zero-crossings of AC to extinguish
arcs when the switch opens, the snap-action was to get the switch
contacts far apart as quickly as possible.

Isaac

 

[Cydrome Leader]

Steve Kraus <screen@spamblockfilmteknik.com> 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?

yeah, they used mercury.

Did people back in the day actually want switches to make loud snaps like
maybe to assure them that the action had taken place?

Old switches were made well and lasted forever. New switches at the box
stores are complete shit and virtually fall apart just mounting to a box.

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.

My guess here is they didn't want to compromise quality and reliability
standards of the tiem to make cheap, short lived crappy swithes like are
OK now.

Even places like hospitals get the wrecking ball before they wear out
these days.

 

[Jon Elson]

On Monday, October 17, 2016 at 7:25:11 PM UTC-7, Steve Kraus wrote:


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.

The switches we have are almost all cam-operated, not snap-action. A bump
on the handle presses a contact arm onto the other contact. These fail
generally by fatigue of the arm, not by burning out of the contacts. They
do seem to last 20++ years in residential use. Most of the ones I've
replaced are most likely the original ones installed when the house was
built, 40 years ago.

Jon