Switch 5v with 3.3v

Hello to all. I have a micro that works by 3.3v,I want to switch a 5v Relay. What kind of buffer I can use? Is ULN2003 good for it? tnx

If there is only one relay then you can use an npn transistor as a switch to switch your relay

Sorry, But I have 5 Relays,All Relays work with 5v DC. Is ULN2003 good for it?

The ULN2003 is going to drop about 1 volt @ 300mA, if supply is 5V relay coil will see about 4V. I would use 5 2N2222s, good for about 800mA.

ti.com/lit/ds/symlink/uln2003a.pdf

Section 6.6, VCE(sat)Collector-emitter saturation voltage

leoncorleone: Is ULN2003 good for it?

yes uln2003 will work in 3.3v. you can go through the below link

http://www.hobbytronics.co.uk/uln2003a-darlington-array