You don't make a transformer, instead you buy a transformer or take one from a product.
The extremely simple inverters have a square-wave output and the voltage is not regulated.
Many electronic products do not work properly when they are powered from a square-wave. They also do not work properly when the voltage is too high or too low.
What are you taking about I sure not making money with that only reason I sell chip is because some one ask where they could get a chip with low cost shipping
what about this circuit eBay Store - mybe80be hobby electronics 12f683 pic16f628 18f4550: pic12f683 pic16f628 18f4550, hobby electronics, network hardware i can use this for use of a simple FAN,