Raspberry Pi power stability notes


Raspberry Pi 1 B+, 2, 3: APX803 chip state via GPIO (Rpi 1,2) or GPU (Rpi 3) flashes the power LED for voltage input less than about 4.65 V. A yellow lightning bolt also is superimposed on the Raspberry Pi display output for low voltage.

It’s not good to have low voltage to the Raspi, you can scramble the SD card, have random malfunctions, and corrupt data. When you see the low voltage icon, stop and get a properly rated power supply and cord. 2.5 Amps is the current recommendation, with a quality micro-USB cable.

DC Voltageicon
> 4.65none
< 4.65yellow lightning bolt

The Raspberry Pi 3+ finally brought Power over Ethernet (PoE) to the Raspberry Pi with gigabit Ethernet, particularly good for high-bandwidth software defined radio applications.

Measure DC input

There is no built-in capability to measure the Raspberry Pi DC input voltage, without adding an external ADC. You can read the APX803 state (OK/low) from the Terminal: