Hello everyone,
I am trying to interface an external tl494 pwm controller to arduino uno but don't know which tl494 pin should be connected to which arduino pin? Waiting for your Response. Thanks in advance

 

The Tl594 has a feedback on pin 3, to control the pwm, make sure pin 4 is low, download the datasheet. You can use pin 1 as a variable control pin for variable voltage in Atx mode.

 

The UNO has 6 Pwm putouts. Why do you need to add the complications of a TL 494?

 

Actually I need a circuit that controls a dimmer and that dimmer controls the Ceiling fan. I am using PWM because you will know the operation of simple dimmer that changes fan speed using potentiometer. When you slows down the ceiling fan the variable resistance in potentiometer increases and fan speed decreases and when you increases speed of fan the variable resistance decreases. Now the point is that I am living in a country having energy crisis and when there is load shedding and you operate the fan slow then it consumes more energy from the ups. So finally I need a circuit that when I increase the fan speed the energy consumes more and when I decrease the fan speed using dimmer it consumes less energy. Thanks Alot

 

Well a TL594 is not the solution,

you need a mains dimmer circuit, you will need to alter the time constant of the triac firing this will alter the mains voltage and control the fan speed, that is how they work.

You will have to interface the triac with an opto-coupler