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Topic: Vin shorted with 5V how did I do this? (Read 222 times) previous topic - next topic

K_Onghena

Hello,

I somehow managed to misuse an Arduino Micro A000053 and now the Vin and 5V are shorted 0Ohm's between them when I measure.

I don't know what I did wrong, it's not much information but maybe somebody knows how this could have happened.

Vin is 14,4V (regulated DC), 5V is connected to 10k pot read by A5 and third pin of pot grounded.

Kind regards,

Kristof

bos1714

#1
Jun 19, 2018, 01:28 pm Last Edit: Jun 19, 2018, 01:28 pm by bos1714
Hello there!

Below is a screen capture of the schematic for the Micro. The Vin pin and the 5V pin are separated by a P-channel MOSFET and a regulator.



It is possible that there was too much current or voltage applied to the Vin pin, and the regulator was damaged, causing a short circuit. If you can, try to measure the Ohms across the input and output pins of the regulator and see what you get.
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DrAzzy

#2
Jun 19, 2018, 02:21 pm Last Edit: Jun 19, 2018, 02:24 pm by DrAzzy
You burned out the regulator, likely by overheating it, since it's a rice-grain size reg, and you were supplying with 14.4v (so 9.4/14.4ths of input power is being dissipated as heat) - so you cant get more than 100mA or so... Many parts fail to near short, so that explains that.

Or you connected power backwards, that'll do it too.
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K_Onghena

When measuring over the regulator I get pin 1 connected to ground, the second and the big one on top of the regulator are shortened and between pin 1 and 2 I have 650Ohm, between pin 3 and the others I don't get a reading.

Is the regulator damaged or is this normal?

Thank you,

Kristof

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