What reference voltages can be obtained from the Arduino Uno board?

What reference voltages can be obtained from the Arduino Uno board?

The board can operate on an external supply from 6 to 20 volts. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may become unstable. If using more than 12V, the voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts.

What is an external reference voltage?

EXTERNAL: the voltage applied to the AREF pin (0 to 5V only) is used as the reference.

What is the default reference voltage on 5V Uno?

If you have an Arduino Due board, the operating voltage is 3.3V. If you have something else – check the Arduino product page or ask your board supplier. So if you have a reference voltage of 5V, each unit returned by analogRead() is valued at 0.00488 V. (This is calculated by dividing 1024 into 5V).

What is the output of an ADC?

An ADC carries out two processes, sampling and quantization. The ADC represents an analog signal, which has infinite resolution, as a digital code that has finite resolution. The ADC produces 2N digital values where N represents the number of binary output bits.

What’s the voltage of the AREF pin on an Arduino?

INTERNAL: an built-in reference, equal to 1.1 volts on the ATmega168 or ATmega328 and 2.56 volts on the ATmega8 (not available on the Arduino Mega) EXTERNAL: the voltage applied to the AREF pin (0 to 5V only) is used as the reference. But that doesn’t help his issue.

Which is the reference voltage for the ADC?

Reference voltage for the ADC = voltage over the ‘voltage divider’. (as long as VCC is not changing too fast (noise – capacitys – inductivities)) So the absolute hight of VCC is not interesting at all. With the 3.3V Arduino DUE you will get the same results.

Can a Arduino switch between internal and external reference voltages?

Otherwise, you will short together the active reference voltage (internally generated) and the AREF pin, possibly damaging the microcontroller on your Arduino board. Alternatively, you can connect the external reference voltage to the AREF pin through a 5K resistor, allowing you to switch between external and internal reference voltages.

When to use the AREF pin as an analog reference?

The AREF pin is not for measuring the ADC voltage, it is for applying voltage for the chip to use as the analog reference. Apply .5vdc to the AREF pin and set analogreference (EXTERNAL). Now the analog I/O becomes much more sensitive to small voltages. 0 – AREF will be 0 – 1023 from the ADC.