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Is there a way to use common/cheap components to put the 3.3V and 5V pins on an Arduino under load, in order to measure if they are giving a correct and stable voltage? Can I calculate a certain load to test?

Something keeps happening to my boards which causes the 3.3V pin to measure the correct voltage when idle, but to spike when put under load, which kills the component I was powering (XBees, which are previously tested working).

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    resistors are as cheap as you are going to get. – ratchet freak Jan 16 '19 at 15:37
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    Arduino 3.3V source is only good for 150mA. The 5V source for 500mA from USB source, and maybe 700-800mA from the barrel jack if the source voltage is up to about 7.5V, and less current as you get up to 9V, and even less with 12V, the poor 5V regulator will heat up and shut down. – CrossRoads Jan 16 '19 at 17:36
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    @jsotola it is powered by the 3.3V pin, and uses I/O pins for communication only – Jethro Jan 17 '19 at 10:15
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    @chrisl Thanks, do you know what situations could be causing the spikes up to higher voltages? No motors or other components were connected while testing these spikes, but there were previously several MOSFET controlled LEDs and other components incl solenoids which the arduino was controlling, powered by 12V VIN. – Jethro Jan 17 '19 at 10:15
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    solenoids and relays can create spikes. The easiest way to mitigate them is using a flyback diode. Though most boards will additionally opto-isolate them from the control pins. – ratchet freak Jan 17 '19 at 10:27

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