zero Cross detection

Other Hardware Motors, Mechanics, Power and CNC
1

I am using this circuit and facing some problem in using H11AA1 IC. Do the 15k resistors have to be of higher power rating than 2W?? Please tell me of their rating, as i used normal ones and they turned black after some time and it gives me 2.5 V constant output. Please help me over this

2

Do the 15k resistors have to be of higher power rating than 2W?

What is the mains voltage you are using?

For 240V then that gives a current of 16mA and I2R gives you a power of 3.84W so I would use a 6W resistor.

3

Thanks to Wawa who pointed out that the two 15K resistors are in series so the current is 8mA. Therefore the total power in both resistors is 1.92W. This gives just under 1W for each.

However you say

Please tell me of their rating, as i used normal ones

What are normal ones? I would consider normal resistors to be quarter watt which means they are still four times over. Never use a resistor anywhere close to the maximum ratings, I would use at least 2W resistors.