Single chip microcomputer 5v controls a relay of 12v, how to connect it?

The current of the optocoupler is 5ma. Connect the 5v resistor 1K, and then ground the pin 1 2.

If you don't answer 3, you don't have to answer 6. If you don't answer 3, you can directly control it with your feet 1.

If the answer can be controlled by foot 6, don't answer this question.

5 whether the collector is connected to 12V, and then check the input current of the relay you use. If it is 12ma,

Then 12V and pin 5 can be connected with a 1k resistor current limiter, and pin 4 can be grounded. So you can use a 5V switch to control your.

12V relay.