I am designing a IR base home light control. for this i use 6 relays and i try to driver it through uln2003. I connect the GND and COM wire with 12 volt power supply and input pins are connect to microcontroller which gives 5 volt supply but OUTPUT will become constant (about 1 to 1.5 voltage) and not change on any logic 0 or 1
closed as unclear what you're asking by Matt Young, Adam Haun, Daniel Grillo, brhans, Nick Alexeev♦ Jun 24 '15 at 19:07
Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.
Here's something that should work:
The circuit below takes into account the open collector operation of the ULN2003. The diode D1 is to prevent kickback when deactivating the relay. Technically this diode is built into the ULN2003, but it never hurts to have an extra!