Operating 12 volt SMPS fan using arduino and ULN2003

bertus

Joined Apr 5, 2008
21,264
Hello,

That depends on the current of the fan.
The ULN2003 can have a short peak current of 600 mA and drive about 500 mA.

Bertus
 

Thread Starter

Ishan Jain

Joined Nov 12, 2016
100
Yes,the current required by the fan is around 500 mA. So can you please provide me the circuit for the same.

Thank you

Ishan
 

Thread Starter

Ishan Jain

Joined Nov 12, 2016
100
I am doing a project in which i m controlling a relay with 2003 ic, So i wish if i could control a 12 volt fan too. Please provide me the schematic if possible.

Thank you
 

MaxHeadRoom

Joined Jul 18, 2013
22,727
If using a mosfet, a relay is not required, also IF a relay IS used the the mosfet could still do the job, is the ULN used for other functions?
Max.
 

Thread Starter

Ishan Jain

Joined Nov 12, 2016
100
I think you didn't get me sir, I m controlling relay with ULN2003 as I m working on home automation and I also want to control a 12 volt fan from ULN2003 so please provide me the connections for that as I have already used ULN2003 in my project.
 

Thread Starter

Ishan Jain

Joined Nov 12, 2016
100
I m using relay for the bulb but the fan is DC so relay can't be used in this case. Therefore I require a different circuitry for that if ULN2003 is not suitable for this application then please tell me how can I drive the same 12 volt fan with L293d motor driver IC.
 

MaxHeadRoom

Joined Jul 18, 2013
22,727
See post #8, it shows a relay being driven by a ULN2003 the relay contact will switch the 12v supply for the fan.
What voltage do you have on pin 12?
Max.
 

Thread Starter

Ishan Jain

Joined Nov 12, 2016
100
I m having 0.69 volts on the output pin of relay and thats why my relay is not workingcoz is not grounding the voltage. please helpme with that too
 

MaxHeadRoom

Joined Jul 18, 2013
22,727
You show the fan being switched from a 220vac source?
You will require a 12v supply if you want to switch a 12v fan.
If this is another fan, then you will need another 5v relay as well as the 12vdc.
Max.
 

Thread Starter

Ishan Jain

Joined Nov 12, 2016
100
if I m using a dc fan of 12 volt then what amendments you will suggest in the existing circuit? whether I should connect 12 volt fan directly to the ULN ic?
 

djsfantasi

Joined Apr 11, 2010
7,586
What is the potentiometer for in the upper left of your diagram? Where is your 5V supply coming from? I don't see one in your diagram. How are you powering your Arduino? Using the 5V pin is not recommended to power the board; it can damage the Arduino by bypassing its internal regulator.

You don't need another relay to power the fan with a wiring change, but you will need a 12V power supply.
 
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