I bought a device that has switching transformer inside it. I am trying to find an off-the-shelf transformer component that has similar characteristics. It steps up 1.5V up to 300V. It is a PCB-mounted component that is about 12x12x12mm in size. Judging by its behavior the winding on the high-voltage side must have a ratio of 200:1 to each of the two windings on the low-voltage side. The two low-voltage windings each have a resistance of 0.4 Ohm and the high-voltage winding is 70 Ohm. The device draws about 600mA of current so the transformer must be rated for at least that much. It oscillates at a rate of 4kHz. Does any of the transformers sold by you have characteristics similar to this?