Shop OBEX P1 Docs P2 Docs Learn Events
Opto-TRIAC or Opto-TRIAC+Power TRIAC? — Parallax Forums

Opto-TRIAC or Opto-TRIAC+Power TRIAC?

MJHanaganMJHanagan Posts: 189
edited 2012-04-03 17:31 in General Discussion
I need turn on a small AC powered solenoid device. My initial thought was to use an opto-coupled driver (e.g. a Fairchild MOC3022) and a power TRIAC (e.g. an NXP BT138-600). The device needs to be capable of switching an AC voltage as low as ~9 VAC (RMS) as well as a chopped ~18 VAC (RMS) voltage. I was looking at the specs for the MOC3022 and saw that it has a maximum output current of 1 A (RMS) so I am wondering if I even need the second power TRIAC? If the current through the solenoid is <1 A (RMS) can I simply use just the MOC3022 without the power TRIAC?

Comments

  • kwinnkwinn Posts: 8,697
    edited 2012-04-03 17:31
    Depends on the solenoid current requirement. From the MOC3022 data sheet "Output on-state current, total rms value (50-60 Hz, full sine wave): TA = 25°C 100 mA . . . . TA = 70°C 50 mA". If the solenoid draws 50mA or less you are ok. It may even work with slightly more than 50mA but at 100mA or more it will at the very least have a short life or blow very quickly.
Sign In or Register to comment.