I am trying to implement the following circuit. I am trying to understand how the resistance values are calculated. I followed this - "how do I calculate resistor value"
According to my optocoupler (SFH6202) datasheet, following are the calculations:
VF(typical) = 1.25V
If = 60mA
So
Vres = V - Vf = 230 - 1.25 = 228.75
R = Vres / If = 228.75/.06 = 3812.5
But the circuit shows two 100K resistors. Am I doing something wrong here?
Also the Power dissipation is:
P = Vres * Ifmax = 228.75 * 0.06 = 13.72 W
The power dissipation seems too high for 1/4, 1/8 or 1/10 W resistors. Am I doing something wrong in this calculation also? Or do I need some special kind of resistors?
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