Hallo every one I am using triac bt136 and moc3021 for fan speed control but fan continue on when not connected led power of moc3021 please help me what I do.

 

Assuming that no parts have failed. . .
Is it a very small fan? Maybe you are getting enough current through the snubber to keep it running.
Try connecting the snubber across the fan instead of across the triac.

 

One thing about triac control of fan speed -when I tried it on my floor fans the sharp edge of the triac turning on resulted in an audible ping on every half cycle. The result was a continuous buzz.

The two solutions that worked without making a lot of noise were using a Variac to reduce the voltage and putting a motor run capacitor in series with the fan which also dropped the voltage across the fan.

 

You can try putting a resistor, say 4.7 K, between the Gate and MT1 of the Triac to avoid false triggering when the Gate is left floating when the Opto not powered ON.

 

You can try putting a resistor, say 4.7 K, between the Gate and MT1 of the Triac to avoid false triggering when the Gate is left floating when the Opto not powered ON.

I doubt it will make any difference. Most triacs I have measured look fairly resistive at about 50Ω between gate and MT1. But I’m a Thomson triac fan, not a Philips triac fan (if you’ll excuse the pun)