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My cat water fountain comes with a spicy USB power adapter

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Re: My cat water fountain comes with a spicy USB power adapter

#131

Post by cesarb »

lxgr wrote: post #108
dylan604 wrote: post #92

Earlier quoted context omitted.

Dips and spikes are routine in electrical power delivery. In my experience, dips are much more likely to be the culprit of damaging equipment than spikes. People are used to protection from spikes with surge protectors, but the only thing that protects from dips is a UPS. I use a small UPS as part of my entertainment equipment. Not because I want to watch TV during an outage, but to keep from damaging the equipment w…

How would a power dip damage an appliance?

> How would a power dip damage an appliance?

For AC motors, the lower voltage might mean they do not have enough power to turn, so all the power they consume becomes heat in the motor windings (and since they're not turning, there's less cooling).

For electronic power supplies, they might either pull more current to maintain the same output (again leading to more heating), might output a lower voltage (and DC-DC converters which consume that voltage might in turn draw more current, again leading to more heating), or they might even misbehave and output an oscillating voltage; they might also detect the power dip and shut down, only to power up again moments later, repeatedly.

A device in an idle stand-by mode is probably the best case, since it's using little power from a supply sized for a much bigger load.

I disagree with the sibling comment that the only protection from voltage dips is a UPS or similar; a simpler protection is an undervoltage relay with a timer, to convert the voltage dip into a power outage (and also prevent the power from being restored too quickly).

Re: My cat water fountain comes with a spicy USB power adapter

#132

Post by maxerickson »

denotational wrote: post #2

This is the sort of thing that almost (but not quite) pushes me to support mandatory certification (enforced by patents/other IP protections) for consumer devices that use a familiar connector like USB. Consumers shouldn’t need to worry about the specific output voltage; the presence of a USB-A connector should indicate that it abides by the specification. The hacker in me hates the idea of enforcing something like t…

USB does control use of their marks, it would probably be new law to prevent use of the physical arrangement.

Re: My cat water fountain comes with a spicy USB power adapter

#133

Post by NelsonMinar »

jdboyd wrote: post #46
wiredfool wrote: post #17

Earlier quoted context omitted.

It's got a CE mark, but it's unclear if it's valid or not. This is a mandatory certification in the EU, like the UL listing in the US. The device is specifying the output voltage, which isn't in spec for the connector, but it is (apparently) accurate.

UL isn't actually mandatory in the US. The only thing mandatory that I am aware of is FCC certification for devices with signals over a certain number of Hz, and they wouldn't care about a USB port being abused.

I recently ran into this buying an EVSE to charge my car. Amazon in the US is full of imports from generic Chinese brands that are half the price of name brands but not UL certified. Many of them say "UL certified cable" which doesn't tell you anything about the entire charging unit, just the wire stock they used.

It's all fraud. And at 40 amps, potentially quite dangerous.

Re: My cat water fountain comes with a spicy USB power adapter

#134

Post by shermantanktop »

thriftwy wrote: post #97
lucideer wrote: post #84

Earlier quoted context omitted.

> mandatory certification (enforced by patents/other IP protections) > The hacker in me hates the idea If the hacker in you really hates this, then why insist on enforcing via means that restrict both vendor and user freedom (IP) instead of regulatory enforcement that exclusively targets vendors & leaves hackers free to hack?

Hackers want not just hack for themselves but share the product of their craft with other parties without going through fences.

Some do. Some don’t. The various uses of the term “hacking” do not universally require tech to be shared.

Long before RMS and other ideology-oriented types, people were adapting commercial tech to local purposes which the vendor didn’t intend and wouldn’t endorse.

Re: My cat water fountain comes with a spicy USB power adapter

#135

Post by dylan604 »

cesarb wrote: post #131
lxgr wrote: post #108

Earlier quoted context omitted.

How would a power dip damage an appliance?

> How would a power dip damage an appliance? For AC motors, the lower voltage might mean they do not have enough power to turn, so all the power they consume becomes heat in the motor windings (and since they're not turning, there's less cooling). For electronic power supplies, they might either pull more current to maintain the same output (again leading to more heating), might output a lower voltage (and DC-DC conv…

* The only protection available as a consumer add-on.

Sure, if the manufacturer wants to increase the cost on the BOM for their PSUs, they can use additional components to survive dips, but who does that on disposable electronic equipment? Hell, even "expensive" TVs don't. I quote expensive since you can now get 65" 4K TVs cheaper than a mobile phone, but that's a tangent. So if you are wanting to protect your electronic equipment with another device readily available that is just plug an play ease of use with no knowledge of electronics, what do you suggest?

Re: My cat water fountain comes with a spicy USB power adapter

#136

Post by insanitybit »

denotational wrote: post #2

This is the sort of thing that almost (but not quite) pushes me to support mandatory certification (enforced by patents/other IP protections) for consumer devices that use a familiar connector like USB. Consumers shouldn’t need to worry about the specific output voltage; the presence of a USB-A connector should indicate that it abides by the specification. The hacker in me hates the idea of enforcing something like t…

> The hacker in me hates the idea of enforcing something like this

As long as you are free to modify the hardware or purchase specific non-conforming hardware I see no reason why this would be painful for a hacker.

Re: My cat water fountain comes with a spicy USB power adapter

#137

Post by shermantanktop »

MattHeard wrote: post #51

I have/had this cat water fountain too (my cats are now happy with a normal bowl) and I believe I just threw the wall wart into a box with the rest of my unused USB A wall warts. A little bit like electrical Russian roulette now, I guess.

I couldn’t get mine to drink from it. They side-eyed it warily and avoided my attempts to entice them.

Cats.

Re: My cat water fountain comes with a spicy USB power adapter

#139

Post by alexpotato »

denotational wrote: post #2

This is the sort of thing that almost (but not quite) pushes me to support mandatory certification (enforced by patents/other IP protections) for consumer devices that use a familiar connector like USB. Consumers shouldn’t need to worry about the specific output voltage; the presence of a USB-A connector should indicate that it abides by the specification. The hacker in me hates the idea of enforcing something like t…

> pushes me to support mandatory certification

It wasn't mandatory but this is one of the main reasons Underwriter's Laboratory was started. The market needed a certification to say "yes, this things does what it's says it does and in a safe manner".

My dad owned a retail store in the 1970s and he distinctly remember being told "Lots of retailers won't carry a brand/item unless it has the 'UL' sticker on it."

https://en.wikipedia.org/wiki/UL_(safety_organization)

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