Need hardware advice: ULN2003A

[Luciano]

Hi,

When you use only one output of the ULN2003A you can drive a relay with
a coil current up to 500mA. (450 mA with 100% duty cycle, N package).
The internal protection diode will suppress the self-induction current when
you deenergise the relay. Do not forget to connect PIN9.
All unused inputs must be tied to GND.

If you use two outputs simultaneously, then the current of each
output is limited to 280 mA. (100% duty cycle, N package).
See the picture below if you use more than two outputs simultaneously.
(The picture is from the datasheet of the ULN2003A).


(Click to enlarge the picture)


(Click to enlarge the picture)

Best regards,

Luciano