23. Anslutning av en relais¶
Supply power to the relais:

Connect an LED to the relais:

Does the LED light up. Why?
Connect the GND of the Arduino with the IN1 of the relay board.
Does the LED light up? Why`

Yes, the LED should light up.
Build the following schematic. It is called an H bridge. It has two LEDs in opposite directions. All four pins of the relais can now be used.

- Which two pins need to be connected to GND to make the blue LED light up?
- Which two pins need to be connected to GND to make the green LED light up?
Exam:
- Explain on the drawing how the H bridge works
- Build the H bridge
- Light up the blue LED
- Light up the green LED