I have always wondered why are we limited to change fan speed only in discrete steps and why not continuously from zero to max value. As it is very annoying when one want a speed in middle of those two discrete steps. Thanks in anticipation!

 

I suspect that the speed is controllred on your fan by switching between taps on the windings. This is just a guess as you have given no information about the design of you fan.

Les.

 

Many small shaded pole motors can be controlled with a triac dimmer circuit for infinite control.
Max.

 

Many small shaded pole motors can be controlled with a triac dimmer circuit for infinite control.
Max.

With the caveat that it may generate a buzzing sound in the fan motor.

 

Many small shaded pole motors can be controlled with a triac dimmer circuit for infinite control.
Max.

Two ceiling fans I bought a year ago, came with 4 step controls but the electrician suggested continuous controls sharing the box with the lights switch.

 

In my car, this is because the speed control knob is not a pot, it's a rotary digital switch. The speed is controlled by a computer that sees the number of clicks from the knob and adjusts the fan speed to preset levels. The design has always bothered me for the reason you described - poor fine control at low speed.

 

I have always wondered why are we limited to change fan speed only in discrete steps and why not continuously from zero to max value. As it is very annoying when one want a speed in middle of those two discrete steps. Thanks in anticipation!

Cost? Simplicity?
How much current does your fan draw compared to less than one Amp for a light.