How too know whether digitalwrite(HIGH, pin_number) sets the voltage to 5 volts or 3.3 volts. I am yet to purchase arduino uno. I want digital pin voltage to be 5 volts. I am aware that thereis a pin already have 5 volts but I want to know only about the voltage output at digital pins.

Sorry if question is too silly. I am not very knowledgable in Electronics.


2 Answers 2


Different boards operate internally at different voltages. This is dictated by the main chip on the board. That main internal operating voltage is also the voltage at which the IO pins operate.

Most "old" Arduino boards operate at 5V. This includes, but is not limited to:

  • Arduino UNO
  • Arduino Mini
  • Arduino Leonardo

Newer more powerful boards, many made by other companies, operate at 3.3V. Again, this includes such boards as:

  • Arduino DUE
  • Arduino MKR1000
  • Teensy boards (v3.0+)
  • chipKIT boards
  • ESP8266 & ESP32 boards

Some boards come in variants that give either voltage - the most notable being the Pro Mini boards from Sparkfun. These come in both 5V and 3.3V variants and it is important to pick the right board for your needs.

In general, though:

  • If it's 8-bit and runs on an ATMega chip it's likely 5V unless otherwise stated
  • All 32-bit boards will be 3.3V unless otherwise stated.

When you use digitalWrite(pin_Number,HIGH); this sets the output pin to 5 V but still if you want to check the voltage you can you a digital multi meter set its knob to DC voltage and connect its positive to the pin and the ground pin to ground and the voltage will be displayed on the multi meter


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.