How much voltage comes as output from Arduino UNO R3 Digital Pins? (I saw 5 volts but i think its wrong)
I am trying to switch relay using digital pins but i am unable to do it relay requires 6v although relay is switching using 5volt pin defined in arduino but not switching when connecting with Digital Pin 13 and Ground
Urgent help needed Thanks in advance
5V, but limited on current. 5V relays usually have lower coil resistance and need more current that an Arduino IO pin can handle. Use an external transistor to increase the coil current flow.
Here's an example of a relay wired up to control a motor for example.
How much voltage comes as output from Arduino UNO R3 Digital Pins?
https://www.arduino.cc/en/Main/arduinoBoardUno
Each of the 14 digital pins on the Uno can be used as an input or output, using pinMode(), digitalWrite(), and digitalRead() functions. They operate at 5 volts.
The 6 analog input pins A0 to A5 can also be used as digital pins.
5v. Max current 40mA, max recommended current 20mA.
Voltage will droop as you draw more current from it (there are graphs in the datasheet, in the Electrical Characteristisics chapter), though, and most 6v relays require more than 20-40mA.
Most 6v relays will work at 5v.
Since the 5v pin doesn't have such a low current limit (it's limited only by your computer's USB power limit (probably 500mA) or the polyfuse).
But you try to do it with a digital pin, and the pin can't supply enough current, so it isn't getting even 5v (due to the voltage drooping because you're trying to draw more current than the chip can supply)... so it doesn't turn on. Note that exceeding the rated maximum current on an IO pin may damage the chip, particularly over time.
You will need to use a transistor (or MOSFET) to switch the power to to the relay, or use one of the (uncommon) relays that can actually be switched directly from a microcontroller pin (look for 5v coil, 25mA or less)
I know you got the answer to your question but your question raises other questions:
Why are you using the arduino ? (school, hobby ?)
Do you have any electronics experience ?
Have you considered buying a book on how to use the arduino that would also cover the electronics questions you might have ?
