I have a Digital Loggers 'IoT Relay' that is controlled by either low voltage AC or DC in order to turn on/off 120VAC loads. How can I control this relay using 5VDC and 12VDC where either, or both, voltages being applied will turn the relay on?

Thanks

 

Connect the two voltages together through diodes for isolation.

 

Connect the two voltages together through diodes for isolation.

If I do that, is it 'ok' if they are both on at the same time?

 

Photo / link to web page / data sheet - Anything - ?

ak

D'oh! I forgot to post this link to the 'Iot Relay' in question.

https://dlidirect.com/products/iot-power-relay

 

If I do that, is it 'ok' if they are both on at the same time?

Yes. The 12volt source will have priority and block the 5 volt source.
Does the 5 and 12 volt sources share a common negative?

 

Yes. The 12volt source will have priority and block the 5 volt source.
Does the 5 and 12 volt sources share a common negative?

No, they do not share a common negative.

 

But they will when connected to the relay module correct?
Can the two sources share a common negative?
Try this arrangement.

 

But they will when connected to the relay module correct?

That is my understanding based on your method.

Can the two sources share a common negative?

They cannot easily share a common negative, since one source is often powered off while the other is in use and vice versa.

For the diodes in your example, would a 1N4007 be the ideal choice?

Thanks!

 

Not ideal but will work OK if that's what you have on hand.

 

Not ideal but will work OK if that's what you have on hand.

What would be ideal?

 

Like a 1N4148 or equivalent.

 

Like a 1N4148 or equivalent.

Thanks