Is it possible to make an output from the arduino output directly to the relay?

Question

Arduino

Good day!
Actually a question. Is it possible to apply a 5v relay directly from the output of the arduino? Or do you need to put a transistor / other between them? As usual, enlighten me, please ..

Answer 1

The output current of the Atmega328 is 40mA. In real life, such a current should not be passed through it. Those. your relay should operate at a current of 15-20mA. If your relay is like that, then you can; if not, then you can’t

Answer 2

Not worth it. The relay uses inductance, so it must be connected in the same way as, for example, a speaker - through a transistor.
I would recommend reading my post How to connect an 8 ohm speaker to an Arduino .