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volt and current measurement dongle from power supply shows 5.00 volts within 4% and current is less than 500 ma but lightning bolt showa undervoltage. WHY?

JAACK
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2 Answers2

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Because the voltage is dropping beneath 4.65V. Presumably there are periods when something kicks in and requires more current. You need a higher amperage power supply.

joan
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Either the voltage is too low AND/OR the resistance of the cable is too high - causing voltage to drop on current peaks.

The Pi is sensitive to very short transients (which are stretched to ~3 sec for display. See Raspberry Pi Power Limitations

Milliways
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