I have a low AC supply that generates 6V. I want to build a step up transformer that can give me up to 120V using a maximum of 300mA. I was trying to build it using 26 gauge magnetic wire, nuts and bolts but so far I have not been successful. Any ideas? Thank you

 

I've found that BUILDING a xformer is no small thing. You could start with an existing one and with add or extract the secondary winding to achieve the goal. I recently found that core resonance may play an important role in such a project. I am interested in a related idea.

Let's say you had something to work with & weren't starting totally without any core or windings.... If you could determine where you were with that design, there are formulas enough to get you close. But secondary windings are subject to many variables such as winding wire diameter (being limited to 26 may be a big problem) and desired frequency. The core material is a critical factor so using just any ferrous metal would be very difficult.

Grab an old monitor or TV and de-soldier the components; there would be a free source of materials. Developing a supply of 120 volts from a 6v input is not too difficult but at what frequency and ...would you need it inverted from DC?

 

If you're talking about ac at 50/60 hz then all you need is a 120 to 6 volt step down and wire it backwards. But at a 20 to 1 ratio (120/6 = 20) you'll also need 20 times the current. So your 120 volts @ 300ma will mean you need at least 6 amps (.300x20) at 6 volts ac ,and that's assuming %100 effient transformer,which ain't gonna happen.