Arduino Stack Exchange
Arduino Stack Exchange

Questions tagged [voltage]

Voltage is the difference in electric potential between two points of an electric circuit, measured in Volts (V). Voltage can be constant (DC) or varying (AC).

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NodeMCU - Vin pin as 5V output?

I know that Vin can be used to power the board but have also been reading that it can be used as a 5V output. Is it possible to assign Vin as an output as I would any other GPIO? If I want to power an LED from GPIO 12, I would assign GPIO: const int…
acpilot
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Measuring li-ion that arduino is running from

I am using a 5v Arduino pro mini (with regulator and power led removed). I have been reading how to accurately measure Li-ion batteries when powering from the same battery you are trying to measure from. Using the 1.1V internal analog reference to…
Lindsay Cox
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How to know positive and negative in breadboard

I have this breadboard, and there is no indication on it about what is positive/negative on it. In comparison, this other breadboard (pic from the internet) DOES have indications: Can anyone give me a hint ?
N Sharma
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Why is my Analog Input channel adding voltage to my signal?

EDIT: Here are the links to the sensor spec sheet (http://www.omega.com/temperature/pdf/HX71.pdf) and manual (http://www.omega.com/Manuals/manualpdf/M4543.pdf) for your reference. I'm using a relative humidity (RH) sensor with an Arduino Mega. The…
L. Paw
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Powering the Arduino with a battery and reading the battery voltage

I am trying to display the battery voltage as it is being used to power the Arduino. I have tried powering the Arduino through the USB and the battery voltage is read accurately when compared to the multimeter reading. But when the battery is…
acho
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How to create a smooth change in voltage?

We are given two voltages A and B between 0 and 5V. So how do I generate a smooth/continuous analog change in voltage from A to B in a predefined time? The current with that varying voltage is 1 ma or less. The output voltage value is described by…
Pete
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Problem with displaying true RMS of the main voltage using Arduino Uno and MAX7219

I want to display the true RMS of the main voltage using an Arduino and a MAX7219. At first, I used of circuit #1 (the following circuit) and the True RMS library. The circuit could successfully return the true RMS and print it on the Serial Monitor…
soheil
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Programmatically-adjustable buck converter module?

LM2596 is easy to use and cheap, but I have to adjust the output voltage using a screw driver. On the web, there was a "hack" that someone posted, but that hack does not seem as clean or stable as using LM2596 as it is intended to be used, using…
Damn Vegetables
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Arduino measuring high-voltage electric fence

I would like to know if someone has experience with measuring high voltages using an Arduino. I know you can use resistors to lower the voltage, however. I want to be able to measure the pulses of an electric fence used to prevent farm animals from…
TeD van Loon
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Digital I/O threshold voltages for ATmega32u4

What are the voltages on a ATmega32u4 (eg Arduino Leonardo) such that a HIGH or LOW is read? I want to ensure that I'm reading the chip reference manual correctly, where Table 29-1 says: VIL: Input Low Voltage, Except XTAL1 and Reset pin Min:…
Tom Hale
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Measuring voltage from -12 to +12 VDC

I'm making a -12 to +12V DC regulated power supply, on which I want to measure voltage and current with Arduino (through a voltage divider, of course). I'm not sure, how to either detect nor measure negative voltage. I could "detect" it via a…
Jakey
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Arduino read thermocouple Type K with ADS1115

I ordered a ADS1115 so I could measure temperature of a type K thermocouple, but I am not managing to get accurate readings. I had it working while having a normal A0 pin, but since the type K table shows pretty low voltages, the 0-1023 scale is not…
Bart
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One LED in 4x4 matrix does not turn on

I'm an art student and absolute beginner to electronics/code - my broader goal is to learn how to control individual LEDs when there are many of them (like 64 or more even, so am learning about shift registers, multiplexing etc. also). I have been…
Miso
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Measured voltage higher than AREF

What happen when a voltage measured by analogRead() is higher than AREF voltage? Example: AREF = 2.5V AO = 3.2V What is the maximum voltage ?
Jacques
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How to calculate required amperage of multiple motors?

I a very simple question about calculating the amperage I need to run 5 stepper motors from my Arduino Uno. If I have 5 28BYJ-48 stepper motors(which are 5V and are said to require about 240mA each) all plugged into 5 separate ULN2003 driving…
KidWithComputer
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