Here is a circuit of electronic fan speed controller:
Speed of the fan can be controlled by the following logic levels on various pins:
This circuit is meant to be used with a 220 VAC power line and a ceiling fan which looks like this:
Typical wattage is 60-80 watts for these fans.
I want to optimize the circuit and I feel that I can get rid of R7, R8, R17 and R19. R7 and R8 appear to be inrush current limiting resistors (am I right?) whereas R17 and R19 are discharge resistors for the capacitors.
I tested the concept and it worked fine without those resistors. However I am not sure about the long term effects.
My concerns and questions are follows:
1) Can I remove R7 and R8 without having an adverse effect on life of the circuit and the fan connected to it?
2) With 200K discharge resistor in place, the capacitor discharges from 220 VAC to under 5 VAC within 2 seconds. Without those resistors, it takes around 8 seconds. Complete circuit will be inside a plastic casing. Is this discharge time acceptable? Are there any safety regulations related to this? Will removing those discharge capacitors have any adverse effect?