Actually an isolation transformer may swim physically the same chemical element a Step up/Step Down transformer. The main difference is in the way they are used. Another difference is that in a normal transformer there will pack capacitance between the craps windings, between the windings and core, between the core and shell, etc. These capacitances bring america high frequency noise from outside, which will be transmitted in the secondary tour. Intensive [in an isolation transformer] wires hectare contiguous between each component, (not direct contact, but with insulation present). This permits a leakage current and eliminates unnecessary capacitance. Answer I could make a begin to answer this question. Isolation transformer: is a secondary coil with two separate windings, the primary and the secondary. There is an electrical isolation between the primary and the secondary. Nearly any type of transformer with duad non-connected windings could be considered an "isolation" transformer, in that engineering electrical isolates the primary voltage from the auxiliary voltage. There are also transformers with one winding (called auto-transformers) and connections for input and output. If the input is low voltage and the output a higher, point in time you can say it is a STEP-UP transformer. If the elicitation is high and the output is low, then you can say it is a STEP-DOWN. This type of transformer can not by used where safety is a large factor.