Is it necessary to put a diode to protect against inductive loads when using this relay module: https://electronica.in.ua/ua/p1530391818-modul-rele-optorazvyazkoj.html?source=merchant_center&utm_source=google&utm_medium=cpc&utm_campaign=20496384634&utm_term=&utm_content=&utm_position=&utm_matchtype=&utm_placement=&utm_network=x&gad_source=1&gclid=Cj0KCQiA57G5BhDUARIsACgCYnzr1Hc-_r7JZN803t2zLyvyxUq7UavU_WRtJD4V1JCbb_WtvSx0odUaAq3NEALw_wcB
Yes, if you have a DC load. You should add one to extend the life of the relay contacts.
... There's probably a diode on the board to protect the Arduino and on-board driver from the relay coil's inductance, but they don't know what you're connecting to the contacts and they don't know the polarity.
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I need to connect 2 devices via relay, which should work in turn. I have drawn a wiring diagram. The diode has a gray stripe which is the cathode (-). Is this diagram correct? I am new to the world of electronics, but I need to do a small project.
Thank you for your response!
ps: DC load
Yep!
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So the diode will only protect the relay contacts from wear?
High voltage spikes on the wiring of the inductive load could also lock-up or restart the Arduino. There are many threads on this forum asking for help with that.
Leo..
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Thank you very much for explanation. I think, I'll add diodes. Can you tell me if my "wiring diagram" is correct?
Most people switch the "+" power lead, rather than common or GND.
The diagram shows nothing to power or control the relay module, so it won't do anything useful.
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The question was about correct connecting the diodes. The relay module is powered from the 5V/GND pins of the Arduino. What else do you need to know?
The inductive kick diodes are oriented correctly in your wiring diagram. The band indicates the diode cathode end.
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Thank you very much, that's what I wanted to make sure of.