Driving 5V and 12V loads with the same ULN2003


I have a need here that requires to drive 3 leds in +5V and one little DC motro with +12V.
May I use the same ULN 2003 to drive all loads ? Each one in one pin of course.

Thank you guys! And girls.


Always check datasheets to find out about maximum ratings and what you can do with components.
An ULN 2003 consists mainly of transistors in a Darlington setup.
There are a few diodes added which will protect the transistors from so called back EMF.
This setup allows for different voltages to be controlled this way, as long as they share GND.

You still need to check whether the loads you plan to use, can be handled by the ULN 2003.
And the common GND implies that you can only control the motor to run in one direction.
Of course there are ways to overcome that, requiring external components.

You must use the "COM" terminal for the +12V for the motor so that the freewheel diodes
are in operation for the inductive load.

The LEDs are not inductive, so its not an issue for them.

If the motor takes more than 500mA stall current, either common-up several channels for greater
current handling or use something more capable (ie MOSFET).

If you need the motor to be bidirectional, you will need an H-bridge, not an ULN2003/ULN2803


Thank you to share your knowledge!
The motor will be unidirectional.