This entire series is so oddly entertaining.

    • phx@lemmy.world
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      1 year ago

      Most stuff will draw what it needs for amps. A power supply that provides insufficient amps may fail to start the device, or the power supply will overheat.

      Supplying too many volts will fry many electronics though.

      If you have a 19V 3A laptop it’ll be happy with a 19V 5A brick, but probably not so much with a 25V 3A brick which may overload a component and release the magic smoke

      • cryshlee@lemm.eeOP
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        1 year ago

        magic smoke

        This is my second time today seeing that term, and never saw it before today. I kinda assumed it was a tongue-in-cheeky way to say toxic fumes that make you hallucinate or get cancer lmao

        Turns out it is a real actual term and I am stupid

        • pavlov@lemmy.world
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          1 year ago

          I’m am electrical engineer and I thought the same as you. Had no clue it’s a defined term

      • samothtiger@kbin.social
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        1 year ago

        Correct me if I am wrong, but doesn’t voltage determine amperage? 12 volts through 6 ohms makes 2 amps, and 6 volts through 6 ohms makes 1 amp, right?

        • phx@lemmy.world
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          1 year ago

          Yes and no. These are AC/DC adaptors so they’re rectifying the AC current (+/- AC to DC) and using transformers, resistors, etc to step down the voltage. Watts is V*A

          On a power brick, the numbers of a matter of how many volts it pushes out and how fast it can push them out (amps).

          The components inside your laptop need a relatively fixed amount of power at a variable amount of current. If it’s working harder, it may pull power now quickly using more watts of power. The components within the laptop are designed with that amount of power in mind and the resistance is fixed within a certain tolerance.

          The brick is similarly designed to provide a relatively constant amount of power at a maximal rate. You’ll notice that a brick heats up with use. Pull power through it faster than capacity and it’ll overheat and die.

          If you compare to home electricity, think of it like this.

          • 110V, 15A appliance in 220V, 15A circuit. That appliance is gonna melt something and catch fire. This is like a laptop with an over-voltage brick

          • 220V, 15A appliance in a 110V, 15A circuit, it’s probably not going to start or run properly. This is a laptop with an under-voltage brick

          • 110V, 30A appliance on a 110V, 15A circuit. It may run for a bit if it doesn’t immediately draw over the 15A, but when it does the breaker trips or a fuse pops (if they’re working). If you have a bad breaker or fuse that doesn’t trip in time, the wires in your wall will actually heat up and either burn out or set your house on fire

          In the home circuit, that 110V is the constant voltage and 15A is a maximum. You can plug in a 1500W (110V@13.6a) microwave, or a 20W (110V@0.18A) wall wart. Just like the circuit from the wall to your panel, your brick has a fixed volts and max amps. Your laptop has a fixed volts and variable amps.