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Possible damage to BBB when voltage testing it?
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Possible damage to BBB when voltage testing it?

by fff_z on Fri Nov 15, 2019 1:44 am

Hi,

I was playing with a potentiometer and testing the 3.3V source on the header

Anyhow, I tested the current between 3.3V pin and the ground pin briefly, and then I tried to test the voltage but accidentally had the potentiometer on diode testing

I was later told that I shouldn't test the current like that without a load

Anyhow, after that my first measurement of the voltage read like 3.6V

Is it possible anything I did damaged the BBB? Its revC

It turns on just fine, but I'm wondering is the slight discrepancy in voltage from the BBB or from my potentiometer?

fff_z
 
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Re: Possible damage to BBB when voltage testing it?

by adafruit_support_bill on Fri Nov 15, 2019 6:59 am

Connecting the 3.3v pin to ground like that will overload and could potentially damage the 3.3v voltage regulator.

But the 0.3v error you are seeing could also be due to an out-of-calibration multimeter. Make sure that you have fresh batteries in it (many multimeters tend to read on the high side when the batteries are weak). And test it against a known reliable voltage reference.

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Re: Possible damage to BBB when voltage testing it?

by fff_z on Tue Nov 19, 2019 5:06 pm

Hi,

I tried with a bran new 9v battery in my multimeter, and with a better wire connection

Now I'm consistently getting 3.45v on the pin using different batteries and the bran new one

When I check on an old arduino, the 3.3v shows 3.29v on the multimeter relative to ground

I saw a similar shift in the BBB 5v output pin as well

I can use a cheap voltage regulator to fix this, but do you think this voltage offset will be seen in the logic output levels as well?
Last edited by fff_z on Tue Nov 19, 2019 5:16 pm, edited 1 time in total.

fff_z
 
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Re: Possible damage to BBB when voltage testing it?

by adafruit_support_bill on Tue Nov 19, 2019 5:10 pm

Sounds like your multimeter is probably reading accurately. I'll check with one of our BB experts to see if they have any recommendations.

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Re: Possible damage to BBB when voltage testing it?

by adafruit_support_bill on Tue Nov 19, 2019 9:43 pm

Our Beagle Bone folks suggest posting on the Beagle Bone forums. They are more familiar with the hardware details of those boards.

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Please be positive and constructive with your questions and comments.