Uploaded January 2010 | Updated September 2026, 2 hours ago

---

This lets me control a relay using TTL logic, such as my Arduino, to switch 120VAC. This has potential for such uses as turning on a space heater 15 minutes before you wake up, turn off a fan after you go to bed, etc. More build information: kennethfinnegan.blogspot.com/2010/01/switching-120vac-with-5v-digital-logic.html