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Topic: there is a problem if i connect 5v relay to the digital output of arduino? (Read 3856 times) previous topic - next topic


kindly, i hv 4 of 5v relays connected to the arduino digital outputs...the relays
some times dont work if the DC supply voltage not fully charged ...so im thinking
of connect the relays on active LOW state...and supply from battry ==> 6v regulator ....so

6v ====>+ relay - <==== 5v arduino output pin (HIGH)    ====================>>>> relay OFF

so if output go LOW

6v ====> relay <===== 0v from arduino   ============ >>>>> relay switch ON

there is a problem if i applyed 6v===><===5v   in OFF state?
if i connect on active high  and use transistor for amplify arduino output ... there will be a problem with current or any other things ???

-------------- help me pls


Not a good method. When the relay is commanded off the arduino output pin will be at +5vdc and the relay will be sending +6vdc to the output pin, bad results.

First before a proper wiring/powering method for you relay can be suggested we need to know how much current the relay coil uses when it's powered up.



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Your answer may already be here: https://forum.arduino.cc/index.php?topic=384198.0


It depends on the resistance of the coil.
If that is at least 150? (that'd result 30mA) then you don't need the transistor (but the diode is still required.) 
"Who is like unto the beast? who is able to make war with him?"
When all else fails, check your wiring!

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