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BTA24-800CW can't switch off 60 W resistive lump

momensalah
Associate II

i am using MOC3063 as an optocoupler and BTA24-800CW as a triac .with 220 V ac and it worked fine (switch on and off) with the 10W,5W,3W resistive loads but when using 60 W incandescent lump it only turn on but not off  

momensalah_0-1753671467464.png

i am using this basic circuit . Even tried with many different resistance value (Rled=100,R=330)

3 REPLIES 3
Peter BENSCH
ST Employee

Welcome @momensalah, to the community!

Your basic schematic only shows the principle of such controls. For clean control and operation, please read the application note AN5114 carefully, where such problems are discussed in detail, e.g. in section 2.4.

Furthermore, you have not specified what you mean by switching on and off: TRIACs are usually used to implement phase angle control. If you are doing the same, are you working with leading-edge or trailing-edge control?

Regards
/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

Hello Mr.peter ,sorry for the late response and thanks for your advice .i read the application note and there was a signficant parameter which is (di/dt)c i thing this what cause the not switching off case (correct me if i am wrong). Here i capture the voltage R the first one is for the 15W resistive which has pluse that make the zerro detection easier and the slope is not that large , for 30W which is the second one you still can see the pulse but the slope and the voltage increase.But when i used the 60W (where there's no detection for zero crossing) there's no pulse any more and it's like a sine wave with large slope so how can i slove this if it was actually the problem(i added a diode to R which success to turn on and off but the light wasn't stable while operating)

 

Also tried the sot223 with the same circuit and it worked well with all different loads