raspberryFruit
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Joined: Fri Sep 16, 2022 12:44 pm

3v - 5v DC relay?

Tue Oct 04, 2022 3:11 pm

I need a relay that is triggered by a 3v3 output pin on the pi. But the relay needs to let through between 3v or 5v on the load side.
Has anyone ever heard of a relay like this? I can't find one anywhere!

I also thought about using a BUFFER gate or an AND gate but I can't find any that are big enough, they're all microcontroller chips.

pcmanbob
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Re: 3v - 5v DC relay?

Tue Oct 04, 2022 4:38 pm

No relay can be triggered by a gpio pin because the current supplied will be to low to drive the relay coil., you would need a driver circuit to enable the relay to be powered by 5V but controlled by the gpio pin 3.3V.

You may be better using a transistor see you other post.. viewtopic.php?t=340982
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mahjongg
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Re: 3v - 5v DC relay?

Wed Oct 05, 2022 12:51 pm

You want to connect a relay to your raspberry PI, then read this viewtopic.php?f=91&t=83372&p=1225448#p1225448 and learn why most relay modules are incompatible with a raspberry PI, and why, and what you can do to get them to work anyway.

pcmanbob
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Re: 3v - 5v DC relay?

Fri Oct 07, 2022 7:11 pm

I though I had already posted this as I remember writing it and producing the diagram , so either it got deleted or it did no post.

So here is the way to control a 5V relay part no. SRD-05VDC SLC using a transistor driver circuit

Image
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