I’m testing Arduino digital output pins with a multimeter. My code is the simplest blink: void setup() { pinMode(13, OUTPUT); } void loop() { digitalWrite(13, HIGH); delay(1000); digitalWrite(13, LOW); delay(1000); } Expected: HIGH ≈ 5.0 V LOW ≈ 0.0 V Actual readings: Sometimes ~4…

[image] devga: I am using simulation Then all bets are off. Simulations are not the real thing, only a rough approximation. They will not be accurate to the level of real hardware.

Arduino digitalWrite() output shows inconsistent voltages on multiple pins

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serge_t November 20, 2025, 4:00pm 21

I believe if you raise the delay very high (5 or 10 seconds) it will end up giving the right voltage.

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Arduino digitalWrite() output shows inconsistent voltages on multiple pins

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