Relay with DC load

Projects Discussion and Showcase Home Automation
1

Hello,

I bought a relay module to use with my home automation project, but on the relay cover are writen only AC voltages and currents, like "10A @ 250Vac ; 15A @ 125Vac". The control are 5Vdc, ok.

I want to control a DC load (1A @ 12Vdc) with this relay module controlled by an Arduino pin (5Vdc).

Can I do this with this relay module? If connect this load (12V and 1A) at the load pins of relay it will be work normally?

Thanks a lot!

2

Hi,

Please point to or photo the exact relay module you have...

And, importantly, what is the load device rated at 12V 1A ??

3

Hi terryking,

The picture below describes the relay module, the DC load and what I want to do.

The load device is a 12V solenoid valve.

Can I do this circuit?

Regards!

4

Yes. 240V relays will happily switch 12V but not the other way around...

5

Hi,

You also need to consider the switching of a DC inductive load like that solenoid. You need a diode (typical 1N4007 type) in reverse direction across the solenoid coil to absorb transient voltage.

See "AC vs DC: Why do I care?" on THIS PAGE.

6

Thank you rw950431 and terryking228 for the answers!

Terry,

Thanks for the link. If I understood this care is applied on loads with large current and with high inductance, like motors. My solenoid is a 1A only. But if I need to use a diode like this, can you post too a picture showing how I can put the diode on the load?

7

showing how I can put the diode on the load?

The diagram you showed seems right.

The diode should be connected as close as possible to the solenoid terminals.

YES, you need a diode even on 'small' inductances like your solenoid.

8

Hi terryking,

Ok, I understood. So I will try to get this diode. Thanks a lot!!!

Regards