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Topic: Arudino Power Jack dosent work? (Read 987 times) previous topic - next topic

agwhiteb0i

Hi, iv been running my arduino UNO rev3, from power jack for at least 2-3 weeks now, iv made a change to run it Off of a power supply for a computer which supplys a constant 12v. this has worked fine for powering to board for a while (~1 week) however there was an issue with a lack of amps, so i combined 3 12v cords (from the power supply) together to tripple to amps being given to the board. This worked fine and the board was being powered. However, i still had a cut off when my player module (playing music) was set to max volume. So i connected a meter inline with the power module and the arudino to see how much amps it was drawing and found it was being given 7v off the 5v pin, and as soon as i connect the meter the board randomly kept restarting. Now, whenever the power jack is connected the board goes into a constant restart. The board still works and is powered fully with the USB cable.

Is my board stuffed?

xl97

maybe regulator is hosed?  (protection is tripping perhaps or something?)

is the source 'stable'?
have you metered the source?
is it backwards?

fungus


this has worked fine for powering to board for a while (~1 week) however there was an issue with a lack of amps, so i combined 3 12v cords (from the power supply) together to tripple to amps being given to the board. This worked fine and the board was being powered.


Exactly how much power did you think the Arduino regulator can handle?


So i connected a meter inline with the power module and the arudino to see how much amps it was drawing and found it was being given 7v off the 5v pin


Not good.


, and as soon as i connect the meter the board randomly kept restarting. Now, whenever the power jack is connected the board goes into a constant restart. The board still works and is powered fully with the USB cable.

Is my board stuffed?


Sounds like the voltage regulator is...did you disconnect everything when you measured it?


No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

Zapro

Well that sounds strange.

The yellow wires from a computer power supply carry the 12V supply. A single of these wires can supply much more current that your arduino can ever take or handle, so it sounds extremelt strange that you chose to parallel three of these.

The only way i see that you could get 7V from a power supply, is when you connect one of the red wires (5 Volts) to the Arduino Ground. Then it will see 12-5V = 7V.

In some rare cases, a PC power supply will need a load on the 5V supply to supply stable voltages. I don't suspect you have a suitable power resistor for loading down the 5V, so use an 12V incandescent bulb (like a car bulb, or halogen)

Try measuring the voltages and check all is right. The yellow wires is 12V, the red 5V, orange 3,3V

Also, try doing a read-up about voltage and current, you seem to be mixing up the terms a bit.

// Per.

pwillard

Feeding the DC jack with 12V is the extreme of "acceptable" because it causes the regulator to "run hot".  I doubt providing more current was going to solve your issue.  You were probably making the regulator overheat and it tries to protect itself by cutting out...   Your supply, I feel, even before adding wires, was adequate "current wise" but you should have been supplying it a lower voltage if you wanted to run things that drew higher current.

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