Hi folks,
I want to make a circuit that'll control the speed of a fan motor (ac/ single phase) uding a decoder. Could anybody suggest me an idea by using decoders or any other simpler circuit/component.
the simplest way is to use a magnet and a reed relay. Stick the magnet to the motor and the reed relay will pulse as the magnet passes by it.
If you want to measure the actual angle of the motor as it rotates, you will need a rotary encoder. Austria Microsystems do a range of these and are easy to use and can detect upto a few 100 rpm with 10 bit accuracy.