I know what I'm talking about, I am a professional working in electrical engineering. Please don't insinuate that I don't, it's unnecessarily insulting.
If you have two power supplies at different voltages and connect them together, there will be a finite resistance through the cable and Ohm's Law applies. Current will flow. With a low resistance and big enough voltage difference, there will be a significant current, and it can trip the supply. This is not difficult to achieve.
The rectifier you're referring to is the flyback diode in that case. But now as you've said yourself, the power supply will shut down if the voltage coming in is too high, which is frequently due to either a polyfuse or an efuse tripping. So it sounds like you're just arguing to argue, while actually agreeing with my point. You said "nothing will happen", but if one shuts off, something has happened.
I don't need to test this, I have done it. I also have quite literally thousands upon thousands of other engineers, books, universities etc backing me up, and you do not. Connecting two USB supplies together is a bad idea and will likely result in one switching off. Don't do it.
Either way, I'm done trying to convince an amateur. Feel free to do what you want.
I don’t know at this point if you have fun trolling around or what.
“If you have two power supplies at different voltages and connect them together, there will be a finite resistance through the cable and Ohm's Law applies.”
That is an error that only a person with minimal knowledge from TV shows can do. That is absolutely bot true for regulated power supplies, SMPS or Linear, becauae (even if the later is called linear) they are not linear. So no, you cannot apply Ohm’s law.
“The rectifier you're referring to is the flyback diode in that case. But now as you've said yourself, the power supply will shut down if the voltage coming in is too high, which is frequently due to either a polyfuse or an efuse tripping”
Noooo I’m talking about the diode at thr end of any SMPS, buck, boost, fly-back or whatever type, or even a linear regulator. Is about how a regulated power supply works: as the voltage goes up in the output, it shuts down, stops the output current, in an intent to liwer the voltage. There is no fuse in 99% of supplies out there, because they have active protection. Is called a transistor, not a polyfuse.
“I also have quite literally thousands upon thousands of other engineers, books, universities etc backing me up”
That is what you think, but you are wrong. Sorry mate. If you would just go to a lab and put 2 power supplies in parallel, like I do pretty much daily, you will see you are wrong.
You are the most ignorant, obstinate and arrogant person I’ve seen in HN… and here is full of it. I’m 100% sure you studied CS in a medicre university, work as sw dev, and think you can talk with an EE. You say you work with electrical stuff, but your other posts reveal you are a SW dev. Obviously you are a liar, and trying to be right when you are sooo obviously wrong.
I do care what you do, because with such an arrogance and incompetence together, you are going to get somebody hurt or killed. Please start studying and stop being so stubborn when you are just wrong!
If you have two power supplies at different voltages and connect them together, there will be a finite resistance through the cable and Ohm's Law applies. Current will flow. With a low resistance and big enough voltage difference, there will be a significant current, and it can trip the supply. This is not difficult to achieve.
The rectifier you're referring to is the flyback diode in that case. But now as you've said yourself, the power supply will shut down if the voltage coming in is too high, which is frequently due to either a polyfuse or an efuse tripping. So it sounds like you're just arguing to argue, while actually agreeing with my point. You said "nothing will happen", but if one shuts off, something has happened.
I don't need to test this, I have done it. I also have quite literally thousands upon thousands of other engineers, books, universities etc backing me up, and you do not. Connecting two USB supplies together is a bad idea and will likely result in one switching off. Don't do it.
Either way, I'm done trying to convince an amateur. Feel free to do what you want.