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I think the popsicle example may be backwards - they must change phase before they can begin to rise above 0 degrees, and the phase change is a tipping point that takes a ton of energy

If they used dry ice, you would have 3-ish phase changes...

2-ish phase changes when dry ice sublimates, then later for the ice in ice cream

Interesting tidbit: It was Sony who actually tried to build the first rice cooker, but they failed so badly that they gave up and pivoted to radios [0]

[0] https://onefromnippon.com/rice-cookers/

One thing this article completely glossed over is that most rice cookers you find these days don't have an outer water reservoir that boils away like the one described in the article (until reading this I thought of those as "Taiwanese style rice cookers" because the only ones I had seen like this were from Taiwan).

There is a difference between waiting for one cup in the outer reservoir to boil completely away for 20 minutes, and waiting for the rice+water mixture to come to a certain temperature.

Edit: I ended up down a rabbit hole about why Taiwanese rice cookers more commonly use indirect heat and found this great article:

https://www.taiwangazette.org/news/2021/10/23/thinking-outsi...

Interesting, so in Taiwan at 110V a Tatung won't have the lid rattle around like mine does at 115-120V in the US?

Tatung even makes rice cookers with stainless steel bowls!

For those in the U.S., Aroma and Elite also make stainless steel inner pots.

That's what I use.

The same bimetallic break was used in old circuit breakers. You would literally have to wait for the metal to cool down before the connection could be restored. Not sure if it's still used or we use something fancier these days?

Bimetallic strips are still used these days, but it is often not the only trigger.

The bimetallic strip is for overcurrent protection over a period of time. For example, if you are running an appliance using a constant 15A on a 10A breaker. The breaker will pop, but not instantly, and I guess you may have to wait a bit for the metal to cool down, though it never happened to me.

But there is also a short-circuit protection, it uses a solenoid to quickly trip the breaker when the current is way over its rating. The fancier types (with GFCI) also pop if the return current is not the same as the input current, this is to prevent electrocution.

It'll trip if you're drawing 10a sustained, you really can only draw 80% sustained to avoid a nuisance trip.

Looking at the curves published here[1], no breaker should trip with a current draw under its rating, the tolerance goes the other way. For example, after 1h, at 30°C, a breaker should not trip if the current is less than 113% of its rating, and it should trip if it is more than 145%.

[1] https://www.tekdok.dk/files/CA908024E_Trip_curve_2021.pdf

Interesting, I've certainly had nuisance trips at <100% looking at https://www.ece.uprm.edu/~lorama/Square%20D%20CB%20Curves.pd... page 36 you can see even at the rated 25c ambient it goes below 1 (though not as low as 0.9, much less 0.8 rule of thumb).

I haven't given it a lot of research because NEC requires 125% (1/.8) for continuous loads (for conductor protection).

Perhaps my experience was hot ambient/panel.

This depends on the country you're in. As far as I understand breakers here are rated for 100% the rating they are labeled as.

Fun fact, breakers get more sensitive during heat waves. Annoying when it happens.

Maybe it is an unintended but actually beneficial effect.

The problem with drawing too much current is that things can overheat, and it is more of a problem during heat waves as well.

My washing machine door works like that; BigClive has a great teardown which was quite helpful to explain to me why I couldn’t open the door! https://youtu.be/PIm7q_U3UEM?si=K6wUtHJe2Jm8tW6M

Here's that same YouTube link, but without the tracking parameter linking you to everyone who clicks on it:

https://youtu.be/PIm7q_U3UEM

Modern circuit breakers are much fancier. They break not only when the current reaches a threshold but also when the currents passing in both directions (i.e. also back through the ground wire) are unequal. This prevents things like grounding through someone's body.

  > Modern circuit breakers are much fancier. They break... when the currents passing in both directions [is] unequal

What you're describing is properly called GFCI[0] — which in some countries is referred to as an RCD[1] — not just a standard circuit breaker.

You can get devices which fit into a standard circuit breaker slot which perform both functions. However a conventional circuit breaker (which are still widely available) doesn't do any of that.

[0] Ground Fault Circuit Interruptor

[1] Residual Current Device

In fact in the US, especially residential, GFCI circuit breakers are not terribly common for 120V circuits, people much prefer and are used to having the GFCI in the outlet, which can of course protect multiple conventional outlets downstream.

But, what is quite common in the last 30 years are AFCIs, arc fault interruptors which are code for pretty much all living area branch circuits (just not bathrooms). These are built in to the circuit breaker. You can get dual GFCI/AFCI breakers, but these tend to be expensive and not commonly used. Nobody wants to have go down to the basement just because of a ground fault in the kitchen. Also the propensity for GFCIs to nuisance trip increases with the length of the branch circuit. There’s also cases where they are specifically disallowed.

GFCI outlets also seem to wear out eventually, whether they trip a bunch or not. Lately everyone I know that's sold a house has had to replace one or more of them due to them failing to work during inspections.

Part of the issue with "not terribly common" is that no one ever retrofits these things into older houses and new houses only get them where code requires it since it's an increased cost.

When I mentioned not terribly common I was speaking specifically of GFCI breakers in the breaker panel box as opposed to GFCI in the receptacle. Even in a retrofit or remodel it isn't common to put GFCI in the panel box for the reasons noted. There aren't 240V receptacles widely available with GFCI so these tend to use the breakers.

They should of course be added to any kitchens or bathrooms. It's cheap insurance.

You can get devices which fit into a standard circuit breaker slot which perform both functions

in the UK such a device is called an "RCBO" aka "Residual Current Breaker with Over-Current (protection)"

good summary here from schneider

https://eshop.se.com/in/blog/post/what-is-the-difference-bet...

Yep I thought my house has that until I tested cheap LED dome light from Aliexpress. It had an exposed screw and I was bare feet in garage (concrete floor). Lesson learned.

> (i.e. also back through the ground wire) are unequal.

You mean neutral or return wire. No current should be normally passing through the ground wire. In fact in the US at least, GFCIs can be used on grandfathered ungrounded outlets. When you buy GFCI outlets they come with little stickers: “No Equipment Ground” to affix on the outlet in that case.

They're still built that way: it has the benefit of properly handling slightly over current for a short period vs massively over-current: the former is permitted and necessary for many loads.

My late model Subaru uses this cheap solution for the protection of the infotainment system. If it trips I need to wait for it to cool down for about an hour.

I assume electric water kettles as well, which shutoff shortly after the water starts boiling.

> The bimetallic component means that one metal heats and expands faster than the other, eventually breaking the circuit.

I thought the circuit that powers the cooking was broken because, when the water has boiled away, heat rises and a magnet holding the circuit closed is weakened by the heat, which allows a spring to pull the magnet away and break the heating circuit. (Magnets are weaker when hot.)

I'm getting multiple downvotes here. Am I wrong? What am I missing?

No idea. You are correct - that's exactly how many rice cookers work.

Technology Connections: https://youtu.be/RSTNhvDGbYI

I came to post this video! But I think it's clear that this isn't the design being describe in the original article: that mentions a double-boiler, which is not in evidence here and TC even mentions the double-boiler aspect of earlier designs at around 9:30 in the video. He also says that he was only able to trace the origin of this design back to the '70s.

So it's possible that earlier designs didn't use magnetism, and the magnet-based design was a simplification of earlier water-boiling-at-100c-based designs.

> I'm getting multiple downvotes here. Am I wrong? What am I missing?

I wouldn't have downvoted you for it, but it sounds like you missed this from the article:

> While the rice cooked in the inset pot, a bimetallic switch measured the temperature in the external pot.

While more modern rice cookers may use curie point magnetic switches, that's not what the original rice cooker used.

The user did not "miss this". They've reacted to it by saying that they have thought rice cookers work differently. Which indeed many of them do.

They replied to a comment about the bimetalic switch in this cooker with "I thought the circuit that powers the cooking was …".

While both you and they are correct that more modern devices work that way, that's not how this one works.

It's possible that they didn't miss that fact, but their comment reads as being a direct response to the discussion of the control circuit of the first rice cooker.

What’s with so many Asian rice cookers advertising “fuzzy logic” and now “neuro fuzzy logic”? Is that just a meaningless buzzword? Or is it something actually useful?

Both. Almost everything today uses some form of it. I think the term stuck with rice cookers because they were advertised that way as an advancement from the binary type cooker described in the article. In that sense, it's a buzzword of sorts. There's a lot of examples of that, like it still being called Unleaded Gas despite it having been so by default for how many decades?

Is it useful? Hard for me to answer - I don't like rice, but most of my family does. They all swear by their Zojirushis and Tigers, so I have to imagine it provides a better cook than the old style.

> There's a lot of examples of that, like it still being called Unleaded Gas despite it having been so by default for how many decades?

Depending on where you live, about 0.35 decades?

> On 30 August 2021 the United Nations Environment Programme announced that leaded gasoline had been eliminated. The final stocks of the product were used up in Algeria, which had continued to produce leaded gasoline until July 2021.

- https://en.wikipedia.org/wiki/Tetraethyllead#Modern_findings

That's interesting, but obviously they meant 'in places where it has been banned a long time', there being countries where that's not the case doesn't stop it being an example of this, that terminology/marketing sticks around outliving a point it might've been making.

The EU (incl. UK at the time) banned it 2.4 decades ago.

> On 30 August 2021 the United Nations Environment Programme announced that leaded gasoline had been eliminated.

Basic availability of leaded is unrelated to how long unleaded has been the default.

Nah. They've had a long time to perfect rice cookers. The $40 Walmart one works fine. If it turns out you use it a lot and you really want the nicer one, then spend the money for it. But honestly the cheap one is fine.

Rice cookers are still a bit of a novelty in Western countries but in Asia they are ubiquitous. It's like microwaves: expensive in the 80s now they are mass produced and sold for 80 dollars.

I find the nicer ones tend to do a more consistent and better job. With the cheap ones the bottom is often drier than the top. Timers are great and so are modes for different types of rice.

I had a $15 Aldi one that worked fine. I'm sure the high end ones are better in some ways, but it's sorta like drip coffee pots, there is only so much you can improve upon.

Zojirushi offers a wide range of rice cookers. We just have the basic one and it works well, but they have higher end ones that cost 4x the price that we bought ours, I’m not sure if the rice is actually better in the higher ends Zojirushis. They even have cheaper ones that use fuzzy logic, it looks more like an economy thing over the traditional non stick pressure based rice cookers.

See: https://en.wikipedia.org/wiki/Fuzzy_control_system

I guess to me that feels basic? Is it really something worth advertising?

It's typical for 50+ year old technology to be considered basic. Especially by those who may not remember the before times.

This same mechanism is how a dryer knows when the clothes are dry.

>This same mechanism is how a dryer knows when the clothes are dry.

I've never had a dryer where that feature actually worked. My newer samsung claims to have that, but the drying time still seems to just use the timer (even when using the sensor setting) and they clothes are almost never 100% dry when the timer runs out. I suspect maybe it'd work if the clothes got dry before the timer ran out, but the timer settings always seem to be just short of how long it'd take to dry a load.

Usually for me it struggles if I'm mixing types of cloth. If there's one pair of denim jeans it'll stop when everything else is dry, but the denim isn't.

Heat pump driers are known not dry clothes 100% too.

Do the InstantPot has this basic control circuit which even the cheapest rice cooker has. I ambnot finding clear information on this online.

From my experience operating it I reckon it does the following: after you fill it and start, it starts heating and measures the time it takes to reach 100°C. This allows it (in the rice program) to figure out the amount of mass present and adjust the simmering time under pressure accordingly.

Using the same trick (in alll programs) it figures out overfilling and aborts for safety reasons.

Edit: I think the only sensor needed is a temperature sensor.

If it had a temperature sensor it could just figure out when the temperature starts rising above the boiling point of water.

No it doesn't. Still prefer my instant pot though because it is so much faster and can make much larger volumes of rice

> There is insulation, for sure, but in addition the temperature of what is effectively a large volume ice cube block must rise above 0C before the popsicles can begin to change phase (melt).

hopefully the "large volume ice cube" is something like a saturated salt or sugar solution so that the ambient temperature it tries to hold is colder than the melting point of the popsicles.

There are also neuro-fuzzy control based devices [Slide #4]

https://users.ece.cmu.edu/~koopman/lectures/ece348/22_contro...

Can one make towel rack/drier using same way?

Thermostats also used to use the bimetal trick