This post explains for the relay.
The Part Number is A5W-K, A-5W-K.
The function of this semiconductor is DC 5V, Solid State relay.
Manufacturers : Fujitsu Microelectronics
Preview images :
This is 5V DC, Solid State Relay.
1. Extremely low profile and light weight
(1) Height: 5 mm
(2)Weight: approximately 1.2 g
2. Meet FCC (Part 68) standard
3. Conforms to FCC rules and regulations part 68
(1) Surge strength 1,500 V
4. High reliability—bifurcated contacts
5. Wide operating range
6. DIL pitch terminals
7. Plastic sealed type
8. Latching version available