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Topic: A cautionary tale with cheap ebay Voltage Regulators. (Read 2 times) previous topic - next topic

cjdelphi


Quote
I can show a stable voltage on video to the device you're powering, but decrease the resistance the voltage increases.


That's probably quite different than saying that the voltage increases when you short them.



the voltage sure does rise when you short them, i'm uploading a video of me just brushing 2 crockadile clips together, i then make it switch between voltage in and voltage out (it alternates). then as i short the clips
you'll see the voltage jump, the voltage reader is correct, confirmed it by the multimeter, but when it gets hot powering a device with a large current the voltage does also increase, but it has to be a large current, eg an arduino alone wont be effected too little current.... but if you start connecting bigger items, motors and things? I dunno, i only discovered it by accident when shorting it once time and blowing a small 5mm LED never thought much of it until this board which displays the voltage on automatically arrived..

So i was playing with it and noticed that the 5? pin regulator on this was behaving the same as the even cheaper boards with an even less wattage rated IC switcher... but still this board can supply more watts big whoop, not interested, what I am interested in is why the voltage increases when shorted briefly or after long periods of heat the voltage goes up, device goes um poof.


dhenry

Quote
the voltage sure does rise when you short them


Sounds like you have defined "short" uniquely.

cjdelphi

http://en.wikipedia.org/wiki/Short_circuit

"A short circuit is an abnormal connection between two nodes of an electric circuit intended to be at different voltages. This results in an excessive electric current/overcurrent"

- wiki


touching the clips results in max amp discharge causing the wires to give off heat. is this not a "short" ? I'm serious.....

dhenry

You probably want to focus on the part where it talks about very low / no resistance.

You cannot have a voltage drop over a wire with no resistance.

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