What happens if you plug two chargers to each other?

[milesuy]

What happens if you plug two chargers to each other?

 

Are the chargers "idiot proof" or smart enough to turn off when it is plugged to another charger?

 

Especially the USB-C chargers, since they have the same socket/port, like the Apple 20W charger and Samsung 45W charger

I'm also curious what happens if it is a USB-A charger, like the Apple 5W charger.

[wolfmcbeard]

I imagine a decent one probably has a fuse or some way of not allowing that.
Cheap ones will probably make a nice bang however 

[mariushm]

Pretty much nothing should happen, that would be my guess.  But I wouldn't try it, because there's all kinds of chargers, various designs, some more stupid than others.

 

A charger only produces as much power as the devices connected to it require.So if you push in energy instead of taking out energy, the charger doesn't need to produce anything and will basically behave like there's nothing connected to the cable.

 

Inside, the chargers are kind of like this : 

 

AC input (90-230v AC) -> filtering / preventing noise from going back into mains -->  optional PFC (boost 90-230v to 400-450v DC) ->  send pulses through a high frequency transformer to produce a lower voltage on the other side)  -> rectification (convert those low voltage pulses on the other side of transformer into a dc voltage, ex 5v/9v/12v) -> capacitors (smooth out the dc voltage and provide some energy when the device connected to charger demands more power suddenly, giving time for charger to ramp up production)  --> output connector/cable

 

Between the rectification and the capacitors near the output there's usually a "tap", where some circuit is added to monitor the output voltage and give feedback to the chip on the high voltage side, with this signal the chip will adjust the number of pulses up and down, to keep the output voltage smooth and to the right level. 

 

The rectification part after the transformer is also like a one way valve, it only lets energy flow from the transformer towards the output cable. So you giving power into a charger should basically only charge up the capacitors near the output connector with some power, and maybe send some feedback signal to the chip (the chip will detect 5v or whatever even though it's idling, not producing anything because it doesn't detect any device connected to the cable)

 

 

[Kilrah]

Nothing if it's USB-C since is designed to not do anything without negotiation given the same plugs. If it's something else then it can be just about anything.