Mercury switches are common in thermostats. There are also mercury relays.
Yeah?
When was the last time you looked?
But, according to the wiki I was sent from here (thanks Peter Morris!) I can’t wait to tell people how the “tilt” alarm and lockdown works in vending machines.
SD rocks!
The tilt mechanism in my pinball machines is a plum bob inside a circular conductive ring.
Yeup.
“Instead of making one larger circuit board, each “card” would instead consist of a 3-D stack of eight, connected together in the middle of the boards using pins sticking up from the surface (known as “pogos” or “z-pins”). The cards were packed right on top of each other, so the resulting stack was only about 3 inches high. With this sort of density there was no way any conventional air-cooled system would work; there was too little room for air to flow between the ICs. Instead the system would be immersed in a tank of a new inert liquid from 3M, Fluorinert. The cooling liquid was forced sideways through the modules under pressure, and the flow rate was roughly one inch per second. The heated liquid was cooled using chilled water heat exchangers and returned to the main tank. Work on the new design started in earnest in 1982, several years after the original start date.”
I believe the whole computer was hand-wired too.
What about the Electrolytic Tank analog computer?
The modules were socketed, but the between socket signal connections were done with hand assembled wire wrapped twisted pairs. The actual length of the interconnects mattered. This style of construction went back at least to the CDC 6600 (however that machine was built from discrete transistors in little modules about 2x3 inches in size. (I have a few in my collection. Seymore Cray is credited with the design of each module himself.)
Many machines of the 60’s and 70’s were built with wire wrapped backplanes, but the use of length calibrated twisted pairs was a bit more special.
Francis Vaughan, I went to see theLee Friedlander: The Cray Photographs. exhibit at Stanford last year. Petty cool. Morehere.
Here’s three: Fluorescent bulbs, primary batteries, canned tuna. Ok, two.
Argh. That looks like $200 I can’t afford to spend, spent.
You do realize that not everyone has changed out their T-stat for a new one, right?
I would bet I could find a dozen Mercury stats in a five minute walk in my neighborhood.
Add to the list trunk/under hood/vanity mirror lights have all used Mercury in the past. Again many of those cars are still on the road.
Sure, if you go far enough back in history you can find all sorts of “unsafe” products (Radithor, anyone?). But, Mercury in significant quantities (not the microscopic amounts in CFLs) has not be used in consumer products in many years. We’re getting to that point with Lead, too. As a EE, that makes my life interesting.
Obligatory XKCD: xkcd: Circuit Diagram
Well houses in my neighborhood date from the mid 50s. When did they stop using Hg in stats? 1980? 1990? Anyone with a stat older than that has Hg in their stat.
Components that are designed to be soldered to a PCB would have a difficult time surviving the soldering process (using a reflow oven) if they contained water. Heck, even trace amounts of moisture in certain components can cause popcorn cracking.
If a component contained moisture by design, it would have to be hand-soldered to the PCB.