Dear Rauf,

The use of Zero Crossing triac drivers is of course the best to avoid noise generation.

But I think its valid only if you have to just turn a load on and off.

However, if you have to take a part of sine wave (of your ac line) midway, where there is potential above zero, there you cannot enjoy the effect of zero crossing to avoid noise. For example in dimmers and speed control, where you have to clip the sine wave above and below zero during its +ive and -ive half cycles.

I have used 3021 to switch on the load (motor) and in its series an LED lit LDR in a dimmer only to change the firing time to get the desired speed of the motor.

Here even if I use a zero crossing triac driver, then it would be good as long as I have to run it at full speed.

Steve, Peter ????

Regards

Babar/