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Electronics => Beginners => Topic started by: PerranOak on October 20, 2022, 02:59:10 pm

Title: TLP3042 Optoisolator Triac: "always" on
Post by: PerranOak on October 20, 2022, 02:59:10 pm

I hooked-up the TL3042 "input side" (i.e. the LED) to a battery with and external LED to see what's happening. I did the same with the "output" side (i.e. the triac).

When the input is connected, the output turns on - all well and good.

However, when I turn-off the input, the output stays on. The output only goes off when I disconnect the output circuit. Then it all "zeroises" and I can start the experiment again.

Is it supposed to stay on under these conditions?

Cheers.

Title: Re: TLP3042 Optoisolator Triac: "always" on
Post by: wraper on October 20, 2022, 03:04:15 pm

Triacs cannot turn themselves off. Therefore they usually are used with AC. These devices shouldn't be used to switch on any load directly. They are only good for controlling triac gate. Datasheet of MOC3042 is much more clear about this. Also this device shouldn't be used for 230V mains voltage, for that you need a 600V part for it to be reliable.

Title: Re: TLP3042 Optoisolator Triac: "always" on
Post by: PerranOak on October 21, 2022, 07:41:06 am

Thank you. I was fiddling around to see how it worked. I’ll look up that datasheet, cheers.