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Relays and Voltage

Posted: Sun Sep 18, 2016 9:56 pm
by occupied
Hello all,

Something I should know the answer to but alas I don't.

I have some relays:
Relay.jpg
Relay.jpg (61.14 KiB) Viewed 741 times
My plan was to run 5V to VCC, GND to GND and 3.3V GPIO to IN... but no dice :(

I then connected 3.3V to VCC and the relay works great :)

So what is the reason the latter worked while the former wouldn't?

Any tips appreciated!

Re: Relays and Voltage

Posted: Sun Sep 18, 2016 10:18 pm
by alexeames
You'll probably find they trigger when connected to GND and are OFF when connected to 3V3.

These kinds of relays are most often HIGH = OFF and LOW = ON. It can be confusing if you don't know :D

Re: Relays and Voltage

Posted: Mon Sep 19, 2016 11:04 pm
by occupied
Thanks for the tip! :)