Power 5V Relay direct from 5V Source

Hey All,

Relatively new to electronics and managed to get the 5V relay working with Arduino which is fantastic.

However I’m wondering why I can’t get my 5V relay to work direct from power source.

The voltage drop across the Input is 5V, similar to Arduino output, yet the relay won’t engage and I can’t figure out why.

I’ve attached a diagram which shows how I’ve wired it up.

Relay Diagram.jpg

How to attach an image

Here's OP's pic:

Relay Diagram.jpg

Looks like you have a relay module (ie relay on a board) not a bare relay? Most of those are active low, gnd to in.

(But that wouldn't explain how your code's working, unless you're digitalWrite()-ing a low there too.)

Hey,

Yes you're correct, it's a module - not just the relay itself.

There's no code - I'd just like to wire it up directly to the power supply and a reed switch.

I'll try using ground....

ltsmash:
There's no code

I saw this:

ltsmash:
managed to get the 5V relay working with Arduino

... and took that to mean a code solution.

Yep that worked, thank-you so much.

So I need to use GROUND instead of the 5V supply to activate the relay module.

Thank-you!

Keen Nosey to know why you have an Arduino in the mix if it's not for its program...

I did post it in "General Electronics" :slight_smile:

I'm just wanting to use a simple Reed Switch to activate a relay - not really arduino related.

Thank-you for your assistance.

Arduino-as-power-supply :wink: