It is ok and reliable to use 5v relay with arduino due 3.3v without logic level shifter ?

Thread Starter

meowsoft

Joined Feb 27, 2021
494
It is ok and reliable to use 5v relay with arduino due 3.3v without logic level shifter ?, what do you think ?
 

dendad

Joined Feb 20, 2016
3,925
Have the Duo drive a transistor and run the relay off 5V.
The Duo will not drive the relay directly as it does not have the current capability on its port pins.
And it is always a good practice to have some isolation between the controller and the load.
A 5V relay may work on 3.3V, but for reliability, use what the relay is rated for.
 

Ian0

Joined Aug 7, 2020
3,525
It is ok and reliable to use 5v relay with arduino due 3.3v without logic level shifter ?, what do you think ?
A 5V relay would probably pull in at 3.3V, but I don't know of any relays that will work at the level of current an arduino could supply. Use a transistor to drive the relay as @dendad said.
And don't forget the diode across the coil.
 

Thread Starter

meowsoft

Joined Feb 27, 2021
494
A 5V relay would probably pull in at 3.3V, but I don't know of any relays that will work at the level of current an arduino could supply. Use a transistor to drive the relay as @dendad said.
And don't forget the diode across the coil.
Is using logic level shifter is more reliable ?, yes... relay will triggered with 3.3v even 2.8v but it's labeled for 5v use
 

Yaakov

Joined Jan 27, 2019
3,609
Is using logic level shifter is more reliable ?, yes... relay will triggered with 3.3v even 2.8v but it's labeled for 5v use
If you know the voltage is OK, that’s half of it. The current is the other half. Can the Arduino deal with the current the relay demands?

A level shifter isn’t particularly important but something that can handle the current is. A transistor is a simple and standard solution to this.
 
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