Guyz will you please help me out, im not good when it come to electronics design. Im building a high and low voltage protector for home appliance, the circuit that im building is on this site **broken link removed** but the part that i dont understand is the first part which are two transformers (X1 and X2). Im not sure whether these are auto-transformers because their secondary ranges 0-24v and for X2 0-12v,is it one type of transformer or what?