Arduino 101 3.3V vs. 5V Output/PWM

Hey guys,
Newbie alert: i've just started playing with the Arduino 101 and was a bit confused with the "3.3V operating voltage" fact. Coming from an Arduino Uno (5V) does this mean that i have to adjust resistors in my circuit (e.g. replacing resistors for running Leds with lower ones)?

If you're only interfacing with basic LEDs, then yes, you'll probably need to reduce resistor values. But if you're interfacing with inputs or outputs from other circuits running off of 5V, you may need to make an interface circuit that provides logic-level voltage translation. The I/O pins are 5V tolerant, but you will need to look at input and output voltage levels (Vil, Vih and Vol, Voh) to make sure the 3.3V and 5V circuits are interpreting the logic levels properly.

thank you very much for your answer! Got it :slight_smile:

jverive:
If you’re only interfacing with basic LEDs, then yes, you’ll probably need to reduce resistor values. But if you’re interfacing with inputs or outputs from other circuits running off of 5V, you may need to make an interface circuit that provides logic-level voltage translation. The I/O pins are 5V tolerant, but you will need to look at input and output voltage levels (Vil, Vih and Vol, Voh) to make sure the 3.3V and 5V circuits are interpreting the logic levels properly.